Forecasts

Below average temperatures, some breezy winds for Thornton’s weekend

We will enjoy dry conditions for the three-day period. However, temperatures will be on the chilly side and Saturday is going to offer up some blustery winds.

For Friday, sunny skies will be above throughout the daytime hours. Conditions will be generally calm and highs will reach the upper 30s. Tonight, cloud cover will increase and lows will dip to a bit below freezing.

Saturday brings some cloud cover but we will remain dry. Highs will reach the low 40s, aided by breezy downslope winds. Saturday night, winds will ease and we will dip to the teens under partly clear skies.

Sunday will see mostly to partly sunny skies above. Highs will only be in the mid to upper 30s but conditions will be calm.

Have a great weekend!

Climatology, Thornton Weather

Thornton’s 2024 weather recap: A very warm year, precipitation comes in near average

Thornton, Colorado's 2024 annual temperature summary. (ThorntonWeather.com)
Thornton, Colorado’s 2024 annual temperature summary. (ThorntonWeather.com)

With the year in the rear-view mirror, we can now take a look back at Thornton’s weather for 2024. In doing so, we see that we recorded our warmest year of the past 18 years and while precipitation came in near average, most of that was seen early on.

The year started with a chill as January saw mercury readings a good bit below average for the month. However, it would end up being only one of two months during the year that didn’t see above average mercury readings.

From February through October, each month saw above average temperatures, some significantly warmer. November did, finally, see things cool down but then December came back to close out the year as the warmest December in 18 years.

Despite the warmth, we did enjoy above average precipitation for three out of the first four months of the year. Then, however, we began to see changes as seven of the next eight months all saw below average levels of precipitation.

We did have some notable weather events during the year.

In March, we saw a strong storm system produce heavy snowfall across much of the Denver metro area. Here in Thornton, we recorded a total of 10.8 inches between March 14th and 15th. Business and schools shut down and roads become quite difficult to travel. As usual, Denver’s official station way out at DIA lagged with only 5.7 inches. Click here to read the National Weather Service summary of the event.

Spring brings severe weather to the Front Range and Mother Nature delivered a doozy of a dose on May 30th. As the sun was setting, hail began to fall and grow in size, reaching from 1.5 inches to 2 1/4 inches in the north metro area including Thornton. Damage was extensive to vehicles and structures with cost estimates now expected to go over $1 billion. More from the NWS here.

As fall arrived, conditions were exceedingly dry and we waited for relief that usually comes in the form of snow. A prolonged period of it did finally arrive and from November 5th to November 9th, Thornton received 10.8 inches of the white stuff. To the south and southeast, the Palmer Divide and adjacent plains saw snowfall measuring in feet. The National Weather Service has more on this event here.

In the end Thornton saw an average annual temperature of 53.7 degrees. This is far above our 18-year running annual average of 50.8 degrees and made 2024 our warmest year during that period. Temperatures ranged from a high of 102.4 degrees on July 12th down to a low of -12.2 degrees on January 16th.

Out at Denver International Airport where the Mile High City’s official readings are taken, they recorded nearly the same. Denver’s official 2024 average came in at 53.9 degrees, well above the city’s 51.2 degrees annual average. This put 2024 in the books in a tie as the third warmest year on record in Denver.

Thornton saw precipitation levels near average with 14.56 inches being recorded during the year. This is in comparison to our 18-year running annual average of 15.27 inches. Four months had above average precipitation, eight were below.

In Denver, as measured at DIA, a precipitation total of 14.12 inches was recorded. This was close to but short of their long term annual average of 14.48 inches per year.

Click here to view Thornton’s 2024 climate report.

Thornton, Colorado's 2024 annual precipitation summary. (ThorntonWeather.com)
Thornton, Colorado’s 2024 annual precipitation summary. (ThorntonWeather.com)
Photography, Thornton Weather

January 2025 top shots: Monthly photo slideshow

Hoarfrost coats the foliage as January 2025 begins. (David Canfield)
Hoarfrost coats the foliage as January 2025 begins. (David Canfield)

As one of our coldest months, January can be a good month to hibernate inside and avoid the outdoors.  But, like any month in Colorado, photo opportunities abound as our monthly slideshow demonstrates.

Snow is not normally dominant in the month but when it does fall, it can create a beautiful blanket of white.  Throw in the amazing sunrises and sunsets we receive in the middle of winter as well as wildlife and a host of other subjects and the imagery can be quite beautiful and stunning.

  • Slideshow updated January 9, 2025
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

Weather History

January 5 to January 11: This Week in Denver Weather History

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This Week in Denver Weather History

January in Denver is probably best known for the cold and our look back at this week certainly has a number of events that include nasty temperatures. We also many high wind events as well as some significant snowstorms.

From the National Weather Service:

31-6

In 1973…the 31st marked the start of a protracted cold spell that extended into January of 1974 when temperatures dipped below zero on 7 consecutive days. Record daily minimum readings occurred on the 3rd and 5th when the temperature plunged to 17 degrees below zero on both days. A record low daily maximum temperature of only 4 degrees occurred on the 5th.

31-7

In 1941…a protracted cold spell through January 7…1942… Produced below zero low temperatures on 7 of the 8 days. A low temperature of 2 degrees on the 3rd prevented a string of 8 days below zero. The coldest days during the period were the 1st with a high of 2 degrees and a low of 9 degrees below zero…the 4th with a high of 2 degrees and a low of 11 degrees below zero…and the 5th with a high of 26 degrees and a low of 12 degrees below zero.

1-5

In 1940…the first days of the month were characterized by a mixture of drizzle…light snow…and fog. Fog occurred on each day. On the 4th and 5th considerable glazing resulted from freezing drizzle. All objects were coated with a glaze on the windward side. This resulted in very slippery streets…which caused several minor traffic accidents. The glaze was not heavy enough to damage wires and cables.

2-5

In 1959…very cold temperatures…to near zero and below…caused power and gas lines…water pipes…and automatic sprinkler systems to break. In Boulder… Merchandise and furnishings were water damaged when pipes burst in a department store…flooding three floors. The temperature was below zero for 38 consecutive hours at Stapleton Airport on the 2nd…3rd…and 4th and plunged to a low of 13 degrees below zero on the 4th.

3-5

In 2017…the first in a series of powerful winter storms brought a period of heavy snow to the north central mountains… Front Range Foothills and Urban Corridor. In the mountains and foothills…the heaviest snowfall occurred along and north of the Interstate 70 corridor. Storm totals ranged from one to around three feet. Eastbound I-70 was closed at Vail and Silverthorne because of poor conditions and several spun-out vehicles. Across the Interstate 25 corridor…heavy snow fell over northern parts of metro Denver north to Loveland. At Denver International Airport…145 flights were canceled. Storm totals in the mountains and foothills included: 19.7 inches 5 miles northeast of Ward…18 inches…17 inches near Brainard Lake and Copeland Lakes; 16 inches…5 miles east-northeast of Nederland and Niwot Ridge SNOTEL; 15.7 inches at Eldora… 14.5 inches at Berthoud Pass; 14 inches at Allenspark and 12 inches at Gross Reservoir. Along the I-25 Corridor…storm totals included: 13.8 inches in Boulder…12 inches at Marston Reservoir…9.5 inches in Niwot…9 inches at Flatiron Reservoir… 8.3 inches in Northglenn; 8 inches at Hygiene…7 inches in Arvada…5 miles west-northwest of Brighton…Frederick… Lafayette…Loveland and 5 miles northeast of Westminster; with 6.5 inches at Ralston Reservoir and Wheat Ridge. At Denver International Airport…there was a mix of rain and snow with only 0.10 inches of snowfall observed on the morning of the 4th.

4-5

In 1996…snow began falling across the Front Range foothills and portions of metro Denver on the 4th. Most snowfall amounts ranged from 4 to 6 inches. Icy roads and blowing snow caused a 22 car accident on I-25 north of Denver… Resulting in an 8-mile traffic back-up for several hours. Snowfall totaled 3.2 inches at the site of the former Stapleton International Airport. North-northeast winds gusted to 22 mph at Denver International Airport on the 4th.

In 2020…a brief period of strong bora winds occurred in and near the foothills during the late evening and early morning hours. Scattered but brief electrical outages were reported. Peak wind gusts included: 84 mph atop Berthoud Pass…83 mph at NCAR Mesa Laboratory; 79 mph at Longmont Municipal Airport; 78 mph…3.5 miles southwest of Superior; 76 mph at Rocky Mountain Municipal Airport and 75 mph east-northeast of Pleasant View. West-northwest winds gusted to 41 mph at Denver International Airport on the 4th.

5

In 1871…a heavy gale in Boulder caused 500 dollars damage.

In 1895…northwest winds were sustained to 36 mph with gusts as high as 68 mph in the city.

In 1899…strong winds occurred in Boulder…but caused only minor damage.

In 1911…northwest winds were sustained to 41 mph in downtown Denver.

In 1915…north winds were sustained to 40 mph with gusts to 42 mph behind a cold front…which produced only 1.0 inch of snowfall.

In 1972…warm Chinook wind gusts to 85 mph were recorded in Boulder at the National Bureau of Standards and to 60 mph at Jefferson County Airport near Broomfield. The high winds caused severe blowing snow in and near the foothills… Completely blocking traffic in some areas…closing schools and industrial plants. Houses under construction were damaged…and falling trees damaged cars in Boulder. An apartment building under construction was blown down in the Denver area. Northwest wind gusts reached 58 mph at Stapleton International Airport.

In 1989…during the early morning hours with temperatures in the mid-to-upper 30’s…0.25 inch of rain fell at Stapleton International Airport

In 1994…occasional high winds blew across the eastern foothills. Wind gusts to 84 mph were recorded in southwest Boulder and 74 mph in north Boulder. There were also reports of 70 to 80 mph winds along Colorado highway 93 in Jefferson County from Golden to Boulder. Northwest winds gusted to 37 mph at Stapleton International Airport. No significant damage was reported.

In 1999…strong downslope winds developed in the eastern foothills. A wind gust to 100 mph was recorded at Wondervu… Southwest of Boulder. West-northwest winds gusted to only 37 mph at Denver International Airport.

In 2007…a storm system brought heavy snow to areas along the Front Range. The most snow fell in and near the foothills of Boulder and Jefferson counties. Storm totals included: 17 inches 8 miles northwest of Evergreen…16 inches near Conifer…15 inches southwest of Boulder and at Eldorado Springs…14.5 inches near Genesee…12 inches near aspen and Estes Parks…11.5 inches in Boulder…11 inches at Perry Park… 9.5 inches near Blackhawk…9 inches in Louisville…7.5 inches in Arvada…7 inches near Erie…6.5 inches near Longmont…and 6 inches at Ralston Reservoir and Littleton. Snowfall totaled 5.6 inches at the site of the former Stapleton International Airport.

5-6

In 1940…snowfall totaled 5.9 inches in downtown Denver.

In 1975…high winds gusting to over 75 mph caused considerable damage in the Boulder area and minor damage in Jefferson County. In Boulder…one home was unroofed… Several power lines were blown down…and a number of homes and commercial buildings were damaged. Northwest winds gusted to 36 mph on the 5th and 38 mph on the 6th at Stapleton International Airport.

In 1980 high winds in and near the foothills shattered windows…tore roofs from buildings…and caused many power outages. Much of the damage was in Boulder…where winds gusted to at least 82 mph. Wind gusts of 80 to 100 mph were common in the foothills. West winds gusted to only 37 mph at Stapleton International Airport on the 6th.

In 1982…2 to 6 inches of snow fell across metro Denver. Only 1.1 inches of snow were measured at Stapleton International Airport.

In 1983…high winds buffeted the foothills with gusts of 60 to 75 mph recorded in the Boulder area. West winds gusted to only 38 mph at Stapleton International Airport on the 6th.

In 1998…heavy snow blanketed the Front Range foothills. Snowfall totals included: 15 inches 8 miles north of Blackhawk; 13 inches at Evergreen and 5 miles east of Nederland; 12 inches in Coal Creek Canyon; 11 inches 8 miles west of Conifer; 10 inches in Sunshine Canyon northwest of Boulder; 10 inches 11 miles southwest of Morrison; 9 inches in South Turkey Canyon; and 8 inches at Eldora Ski Area. Snowfall totaled only 1.8 inches at the site of the former Stapleton International Airport.

6

In 1903…northwest winds were sustained to 45 mph with an extreme velocity of 48 mph. The Chinook winds warmed the temperature to a high of 66 degrees…which was a record maximum for the date. The low temperature dipped to only 35 degrees.

In 1962…strong winds caused nearly 14 hundred dollars in damage 2 miles north of Boulder. West-northwest Chinook winds gusted to 33 mph at Stapleton Airport in advance of a cold front that produced northeast wind gusts to 43 mph along with some blowing dust and 0.1 inch of snow.

In 1972…a wind gust to 69 mph was recorded at the National Bureau of Standards in Boulder. Only minor damage occurred. Northwest winds gusted to 33 mph at Stapleton International Airport.

In 2007…a large avalanche swept two vehicles off U.S. Highway 40…near Berthoud Pass…and partially buried them. The slide covered all three lanes of the highway. Eight people were in the vehicles…but only one person was seriously injured. He suffered several broken ribs. The slide was approximately 200 feet wide and 15 feet deep.

In 2020…high winds developed in the foothills early in the morning. Peak wind gusts included: 99 mph…3 miles north-northeast of White Ranch Open Space; 85 mph at the junction of state highways 93 and 72…82 mph at NCAR Mesa Laboratory…78 mph near Superior. West-northwest winds gusted to 47 mph at Denver International Airport.

6-7 Continue reading January 5 to January 11: This Week in Denver Weather History →

Climatology, Thornton Weather

December 2024 weather recap: Thornton sees its warmest, one of its driest Decembers of the past 18 years

Thornton, Colorado's December 2024 Temperature Summary. (ThorntonWeather.com)
Thornton, Colorado’s December 2024 Temperature Summary. (ThorntonWeather.com)

Warm and dry would the operative words as we look back on December 2024’s weather. Temperatures were stubbornly mild and precipitation of any kind was scarce.

The month started as most recent months with mild and dry conditions. The first eight days saw no precipitation and temperatures well above normal. On the 9th of the month, we finally saw a break with some light snow and a couple days of below normal mercury readings.

We then returned to the persistent pattern of above normal temperatures and dry conditions for the next two weeks. On Christmas night, it wasn’t snow that arrived but rather rain, as temperatures were just too warm for the white stuff.

Dry and mild conditions then returned until New Year’s Eve when a surprise, concentrated band of snow moved through in the evening. It brought some light snow and wreaked havoc on the roadways.

Thornton’s overall average temperature for December 2024 came in at 38.3 degrees. This was far above our 18-year running average for December of 30.9 degrees. It also was our warmest December over the same period, besting last year’s 37.1 degree average.

Temperatures ranged from a maximum of 67.4 degrees on the 20th down to a low of 17.3 degrees on the 10th.  Only three days over the month saw below average high temperatures.

Out at Denver International Airport where the Mile High City’s official records are kept, it was warm as well. Their average monthly temperature came in at 39.4 degrees, well above the long term Denver average for December of 31.2 degrees. That put the month into the books as the 9th warmest December ever recorded in Denver.

Precipitation was sparse during the month to say the least. Thornton recorded 0.20 inches, most of which was the result of rain versus snow melt. That is less than half of the 0.44 inch 18-year average for December in Thornton and our third driest December over that period.

Out at the airport, Denver saw a mere 0.04 inches of precipitation in December, all of it on the last day of the month. That was well below the city’s 0.35 December average. That put December 2024 into the Denver weather books as a tie with 2004 and 1890 for the 8th driest December on record.

Snowfall was scarce as well. Thornton recorded an even 2.0 inches, most of which fell on the 31st. This was far below our 18-year December average snowfall of 8.1 inches. It was our second least snowiest December of the past 18 years.

For Denver, as measured at DIA, the month yielded 1.4 inches of the white stuff, all of which fell on the evening of New Year’s Eve. That was far below the 8.0 inch average Denver has recorded since 1882. It also put December 2024 into a tie with last year as the 18th least snowiest December on record.

Click here to view Thornton’s complete December 2024 climate summary report.

Thornton, Colorado's December 2024 Precipitation Summary. (ThorntonWeather.com)
Thornton, Colorado’s December 2024 Precipitation Summary. (ThorntonWeather.com)
Climatology, Thornton Weather

Thornton’s January 2025 preview: Cold temps, not much snow the norm

Thornton, Colorado's January Weather Preview.
Thornton, Colorado’s January Weather Preview.

As we begin the new year the winter chill begins to set in.  While January can see its share of extremes, the month historically sees stable temperatures and is usually relatively dry.

January ranks as the second coldest month in Denver next to December with average temperatures remaining virtually the same from the start to the end of the month.

In terms of snowfall, the month only ranks as the sixth snowiest and it is not uncommon for it to be quite dry.

What does January 2025 hold for us?  Follow the link to find out.

For the complete January preview including a look at historical averages and extremes, click here. 

Photography, Thornton Weather

December 2024 top shots: Monthly photo slideshow

December 4, 2024 - The crescent moon and Venus in the evening sky. (Al Feuerborn)
December 4, 2024 – The crescent moon and Venus in the evening sky. (Al Feuerborn)

The month of December can offer everything from bone dry conditions to bone chilling cold and monstrous snowstorms.  The weather and wildlife all afford an abundance of photo opportunities as our December photo slideshow shows.

Leaves have fallen from trees now and the landscape can sometimes look quite stark.  However it only takes a quick shot of snow to change that picture greatly.  Throw in gorgeous sunrises and sunsets, plenty of wildlife big and small, kids playing and much more and the month can be quite colorful and eventful.

  • Slideshow updated December 31, 2024
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

Showcasing images captured by ThorntonWeather.com readers as well as some of our own, our monthly slideshow covers the entire gamut of weather-related imagery.

Sunsets, sunrises, wildlife and of course every type of weather condition are vividly depicted in images captured from yours and our cameras.

What is missing in the slideshow above?  Your photo!

Our monthly photo slideshow is going to feature images that we have taken but more importantly images that you have captured.  The photos can be of anything even remotely weather-related.

Landscapes, current conditions, wildlife, pets, kids.  Whimsical, newsy, artsy.  Taken at the zoo, some other area attraction, a local park, a national park or your backyard.  You name it, we want to see and share it!

Images can be taken in Thornton, Denver or anywhere across the extraordinary Centennial State.  We’ll even take some from out of state if we can tie it to Colorado somehow.

We’ll keep the criteria very open to interpretation with just about any image eligible to be shown in our slideshows.

What do you win for having your image in our slideshow?  We are just a ‘mom and pop’ outfit and make no money from our site so we really don’t have the means to provide prizes.  However you will have our undying gratitude and the satisfaction that your images are shared on the most popular website in Thornton.

To share you images with us and get them included in the slideshow just email them to us or share them with ThorntonWeather.com on any of the various social media outlets.  Links are provided below.

So come on, get those camera’s rolling!

Weather History

December 29 to January 4: This Week in Denver Weather History

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This Week in Denver Weather History

The end of the year and beginning of the next can be an eventful period in terms of weather in the Denver metro area. Looking back at this week in Denver weather history there are certainly periods of cold and snow but perhaps most notable are the number of damaging wind events.

From the National Weather Service:

25-31

In 1980…temperatures were unusually warm during the week between Christmas and New Year’s. High temperatures for the week ranged from the mid-50’s to the mid-70’s. Four temperature records were set. Record highs occurred on the 26th with 68 degrees…the 27th with 75 degrees…and the 30th with 71 degrees. A record high minimum temperature of 41 degrees occurred on the 27th.

27-29

In 1983…a second surge of bitter cold air in less than a week was less intense. Record breaking low temperatures of 12 degrees below zero on the 28th and 15 degrees below zero on the 29th were accompanied by 3.7 inches of snowfall and northeast winds gusting to 23 mph.

28-29

In 1906…a trace of snow fell on both days…which along with a trace of snow on the 5th…was the only snow of the month…ranking the month the second least snowiest December on record.

In 1970…wind gusts to 87 mph were recorded at the National Center for Atmospheric Research in Boulder. Winds gusted to only 46 mph in downtown Boulder. Damage was minor.

In 2006…while metro Denver residents were still digging out from the heavy snowfall and blizzard that occurred on December 20-21…the second major winter storm in a week buried the city and the eastern foothills again in more deep snow. Heavy snowfall ranged from 1 to 2 1/2 feet in the foothills and from 6 to 18 inches across the city. Another slow moving storm system centered over the Texas panhandle produced deep upslope flow over the high plains and against the Front Range mountains. The storm produced blizzard conditions over the plains mainly south of Interstate 76. Interstate 70 as well as other roads and highways was closed from Denver to the Kansas line due to snow and blizzard conditions. Greyhound was forced to cancel all bus trips from Denver. The heaviest snow fell in and near the foothills and south of Denver over the palmer divide…where north winds sustained at speeds of 20 to 30 mph with gusts to 40 mph piled the snow into drifts 4 to 14 feet deep. In the city…the heavy snowfall persisted for a total of 29 hours. Snowfall totals across metro Denver included: 17.5 inches at Ken Caryl; 15 inches 3 miles south-southeast of Morrison; 14 inches in Boulder and lone tree; 12 inches in Castle Rock and Highlands Ranch; 11 inches in Wheat Ridge; 10.5 inches in Littleton; 10 inches in Arvada…Broomfield…and Louviers; and 8.5 inches in Lakewood and Thornton. Officially…snowfall totaled 8.0 inches at Denver Stapleton. North winds sustained to 25 mph with gusts to 32 mph produced some blowing snow at Denver International Airport. In the city…this second storm increased the total snowfall for the month to 29.4 inches…making the month the third snowiest on record. In the foothills the snow fell at a rate of 3 to 4 inches an hour at times. Total snowfall in the foothills included: 30 inches near Genesee; 29.5 inches 12 miles northwest of Golden; 25 inches in Evergreen and near Bergen Park; 24 inches near Conifer; 23.5 inches 3 miles southwest of Golden and near Gold Hill; 23 inches near Jamestown; 22.5 inches in Rollinsville; 19.5 inches in Aspen Springs; 19 inches near Blackhawk; 18.5 inches at Nederland; 16 inches in Indian Hills…at Intercanyon…and in Eldora; 15.5 inches at Echo Lake; and 12 inches near Ralston Reservoir. The total cost of snow removal just at Denver International Airport from this storm and the previous storm was in tens of millions of dollars. The airport estimated up to 6.7 million dollars in extra costs for contractors…overtime…equipment…de-icing chemicals…and other expenses. The two storms cost the airport 4.6 million dollars in loss concession revenues. United Airlines reported lost revenue of over 25 million dollars from the two storms…while Frontier Airlines lost an estimated 12.1 million dollars.

29

In 1997…high winds persisted mainly in and near the foothills. Strong cross winds gusting between 60 and 70 mph blew a rental truck off the roadway in northern Jefferson County near the Coal Creek Canyon road. West winds gusted to 33 mph at Denver International Airport.

In 2005…high winds were recorded across metro Denver. Peak wind gusts included 75 mph near Chatfield Reservoir and 64 mph at Denver International Airport. No damage was reported.

In 2017…high winds developed in the Front Range foothills west and northwest of Denver. Peak wind gusts included: 98 mph…2 miles south-southeast of Gold Hill…91 mph…3 miles south of Gold Hill; 89 mph near Aspen Springs; 86 mph…4 miles east-northeast of Nederland; 83 mph…3 miles southwest of Jefferson; 77 mph near Rocky Flats; with 75 mph near Aspen Springs.

29-30

In 1898…heavy snowfall totaled 6.2 inches in downtown Denver. Northeast winds were sustained to 35 mph with gusts to 40 mph on the 29th.

In 1912…strong winds buffeted Boulder…causing hundreds of dollars damage. The winds were described as one of the most terrific in the history of the city.

In 1923…a cold wave caused temperatures to plunge 58 degrees in 24 hours. The temperature was 54 degrees at 2:00 pm on the 29th and only 4 degrees below zero at the same time on the 30th. The low temperature of 14 degrees on the 29th was the high temperature on the 30th. The low temperature on the 30th dipped to 10 degrees below zero. Light snowfall totaled only 0.7 inch. Northeast winds were sustained to 23 mph on the 29th.

In 2008…very strong Chinook winds blasted areas in and near the foothills of Boulder and Jefferson counties. The wind blew down trees and power poles…downed electrical lines and fences…and damaged homes and vehicles. Scattered power outages were reported along the Front Range. In metropolitan Denver alone…24000 Xcel customers were affected by the outages. Four planed were damaged at the Vance Brand Municipal Airport in Longmont…one was heavily damaged. Insurance companies estimated up to 7 million dollars in damage. Peak wind gusts included 87 mph at the national wind technology center…86 mph…2 miles north of Longmont; 77 mph at Erie…and 75 mph at Lafayette. On the 30th…a peak wind gust to 47 mph was recorded at Denver International Airport.

In 2021…the combination of very high winds and extremely dry conditions produced the most destructive wildfire in Colorado history (approximately 2 billion dollars). It was also one of the costliest in U.S. history.  The Marshall Fire was driven by wind gusts from 75 mph to 100 mph as it raced across southeast Boulder County and quickly consumed 6200 acres.  Governor Polis issued a State of Emergency.  U.S. President Joe Biden responded to the fires by expediting a Major Disaster Declaration…which unlocked federal aid for individuals and public infrastructure. The Marshall Fire destroyed or damaged over one thousand homes and businesses…along with hundreds of trees.  The fire perimeter included the cities of Marshall… Superior…Louisville as well as unincorporated sections of Boulder County. A total of 45000 people were evacuated from Superior…Louisville…and portions of Broomfield; 26000 residents were without power. In all…1084 homes within the fire perimeter were destroyed and 149 were damaged. Seven commercial properties were destroyed and 30 other businesses damaged. There was one confirmed fatality in Marshall. An elderly resident in Superior was missing and presumed dead. Six people suffered minor burns. In Arvada…a Discount Tire store collapsed. One employee was treated for minor injuries. Semi-trucks were blown over along CO93 and C470 which forced road closures. The high wind smashed car windows. Just prior to the Marshall Fire…the Middle Fork Fire was reported in northern Boulder County. It was contained that day and no structures were burned. Peak wind gusts included: 115 mph in northwest Arvada near CO93…110 mph at the junction of CO93/CO72…108 mph…3 miles southwest of Boulder; 103 mph near White Ranch Open Space…102 mph near Crisman…98 mph at the National Wind Technology Center; 90 mph near Marshall…81 mph at C470 and south Wadsworth…and 75 mph in Boulder. At Denver International Airport…a peak gust of 40 mph was observed from the west.

30

In 1875…snow fell from the early morning into the early evening. While the amount of snowfall was not recorded… Precipitation from melted snow totaled 0.53 inch. Good sleighing was reported…so snowfall must have been 5 inches or more.

In 1895…northwest winds were sustained to 60 mph in the city.

In 1897…west winds sustained to 52 mph with gusts to 60 mph warmed the temperature to a high of 55 degrees.

In 1912…west winds were sustained to 48 mph with gusts to 52 mph. The Chinook winds warmed the temperature to a high of 50 degrees.

In 1928…snowfall was 0.1 inch in downtown Denver. This was the only measurable snow of the month…ranking the month the third least snowiest on record in the city.

In 1990…strong downslope winds buffeted the eastern foothills. Wind gusts to 91 mph were recorded atop Table Mesa in southwest Boulder…while a gust to 94 mph was clocked at Rollinsville. The high winds caused whiteout conditions due to blowing snow along some highways south and north of Boulder. The high winds downed power lines near the Rocky Flats plant south of Boulder.

In 1998…high winds continued to buffet areas in and near the foothills. Near Evergreen…a 100-foot-high blue spruce crashed down on the roof of a home…splitting the corrugated metal roof in half. Fortunately…the tree… Which measured 10 feet in circumference…only penetrated the home’s interior in a few places. Peak wind reports included: 90 mph at Wondervu…88 mph at the Rocky Flats test facility…83 mph near Conifer…and 82 mph atop Blue Mountain near Coal Creek Canyon. West winds gusted to 39 mph at Denver International Airport.

30-31

In 1886…heavy snow totaled 6.5 inches in downtown Denver. Most of the snow…4.5 inches…fell on the 31st. North winds were sustained to 18 mph.

In 1928…snowfall of 0.6 inch was the only measurable snow of the month in the city.

In 1947…post-frontal heavy snow totaled 6.3 inches over downtown Denver. Most of the snow fell on the 30th. North winds were sustained to 17 mph on the 30th.

In 1995…the foothills west of Denver received 5 to 9 inches of new snow…except for Bailey where 11 inches of snow were measured. No snow fell at the site of the former Stapleton International Airport.

In 2021…the first significant snowfall of the season finally made its mark…impacting the mountains…foothills…and nearby plains with much needed moisture. In the mountains and foothills…storm totals ranged from 6 to 15 inches. Elsewhere 5 to 10 inches of snow fell west of I-25…with 3 to 7 inches east of the interstate.  At Denver International Airport…4.5 inches of snow was observed.

31 Continue reading December 29 to January 4: This Week in Denver Weather History →

Weather History

December 22 to December 28: This Week in Denver Weather History

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This Week in Denver Weather History

The period around the Christmas holiday has historically been a pretty eventful one for the Denver metro area. Our look back at this week in Denver weather history showcases a wide variety of extreme conditions. From powerful, damaging winds to extreme cold to monstrous blizzards, we can and have seen it all.

From the National Weather Service:

17-24

In 1924…a prolonged cold spell occurred after mild temperatures during the first half of the month. Most low temperatures dipped below zero with the coldest reading of 15 degrees below zero occurring on the 24th. The high temperature of only 5 degrees on the 18th was a record low maximum for the date.

18-24

In 1998…a vigorous cold front with north winds gusting as high as 38 mph at Denver International Airport on the 18th dropped temperatures from a high of 51 degrees to a low of just 6 degrees before midnight. The arctic air mass that settled over metro Denver produced intermittent light snow and a week-long protracted cold spell that caused low temperatures to plunge well below zero for 6 consecutive nights. The coldest temperature was 19 degrees below zero on the morning of the 22nd. High temperatures climbed only into the single digits on 4 consecutive days…from the 19th through the 22nd. At least 15 people…mostly homeless… Were treated for hypothermia at area hospitals. The bitter cold weather was responsible…either directly or indirectly… For at least 5 fatalities. Three of the victims died directly from exposure. The cold weather also caused intermittent power outages. Following the cold snap… Thawing water pipes cracked and burst in several homes and businesses…causing extensive damage. Only one temperature record was set. The high temperature of only 7 degrees on the 19th set a record low maximum for the date.

19-23

In 1990…a surge of very cold arctic air invaded metro Denver. Many temperature records were broken as the mercury remained at or below zero for 85.5 hours at Stapleton International Airport…making it the third longest period of subzero readings in 118 years of record keeping. On the morning of the 22nd…the mercury plunged to 25 degrees below zero…which equaled the all-time record low temperature for the month set on December 24…1876. In the foothills southwest of Denver at tiny town…the mercury plunged to 33 degrees below zero on the morning of the 21st. On the same morning at Castle Rock the temperature dipped to 26 degrees below zero. During the period…other daily temperature records were set at Denver…including: record low maximum of 3 degrees below zero on the 20th and a record low of 17 degrees below zero on the 23rd. The record low was equaled with 16 degrees below zero on the 20th and 21 degrees below zero on the 21st. Snowfall totaled 2.7 inches at Stapleton International Airport from the 19th through the 21st.

20-22

In 1933…strong downslope winds produced a warm spell. Low temperatures of 43 degrees on both the 20th and 21st and 41 degrees on the 22nd were record high minimums for those dates. High temperature of 67 degrees on the 21st was a record maximum for the date. High temperatures of 56 degrees on the 20th and 69 degrees on the 22nd were not records; however…the 69 degrees was the warmest of the month. West to northwest winds were sustained to 20 and 24 mph on the 21st and 22nd respectively.

20-23

In 1918…light snowfall on each day totaled 12.0 inches over downtown Denver. Northeast winds were sustained to 16 mph on the 21st.

20-25

In 1983…an extremely bitter cold spell occurred. The temperature remained below zero for 115 hours in Denver… The longest sub-zero period on record. The mercury dipped to 21 degrees below zero on the 21st…the coldest recorded temperature in over 20 years. The cold was accompanied by winds that plunged chill factors to 50 to 70 degrees below zero. Two people froze to death in Denver; both were found outside dead of exposure. Numerous cases of frostbite were reported. Hundreds of water pipes broke from the intense cold…water mains and natural gas lines also fractured…and electricity consumption reached record levels. Light snow totaling 5.8 inches fell at times…and holiday traffic was delayed at Stapleton International Airport for several hours. Eight daily temperature records were set at the time. The all-time record low maximum temperature for the month of 8 degrees below zero on the 21st still stands today. Other temperature records still standing include record low maximum temperatures of 5 degrees below zero on both the 22nd and 23rd and 4 degrees below zero on the 24th.

21-22

In 1969…strong winds raked the eastern foothills in Boulder and Jefferson counties. Wind gusts to 115 mph were recorded at the National Center for Atmospheric Research in Boulder…while in downtown Boulder winds gusted to 75 mph. Some damage occurred.

In 1981…a snow storm dumped 3 to 8 inches of snow across eastern Colorado. Snowfall totaled 6.8 inches at Stapleton International Airport where north winds gusted to only 17 mph.

In 2011…large scale lift from an upper level low combined with a deep easterly upslope flow behind a cold front to produce heavy snow in and near the Front Range foothills and Palmer Divide. Storm totals ranged from 1.5 to 3 feet in the Front Range foothills…with 1 to 1.5 feet along the urban corridor. In the Front Range foothills and Palmer Divide…storm totals included: 36.5 inches…7 miles southwest of Boulder; 32 inches…12 miles northwest of Golden; 28 inches at Genesee; 24.5 inches…3 miles west of Jamestown; 23 inches at Bergen Park; 21 inches at Evergreen and Gross Reservoir; 19 inches near Eldorado Springs and 3 miles west-southwest of Conifer; 17 inches…4 miles south- southwest of Tiny Town; and 13.5 inches…15 miles north of Elizabeth. Along the urban corridor…storm totals included: 18 inches in Golden; 14.5 inches in Boulder…13 inches at the National Weather Service in Boulder; 12.5 inches…5 miles south-southwest of Arapahoe Park; 12 inches at Lone Tree; 11.5 inches in Broomfield; 11 inches in Arvada…4 miles northwest of Elbert…Niwot and Wheatridge; 10 inches in northwest Denver; with 7.3 inches at Denver International Airport.

21-23

In 1924…heavy snowfall totaled 7.9 inches over downtown Denver. During the storm north to northeast winds were sustained to 21 mph. Temperatures were quite cold…ranging from a high of 24 degrees on the 21st to a low of 5 degrees below zero on the 23rd.

In 1964…high winds were recorded along the eastern foothills. A wind gust to 100 mph was registered at Jefferson County Airport near Broomfield. In Boulder… Where many thousands of dollars in damage occurred…warm Chinook winds gusted in excess of 45 mph downtown. A wind gust to 82 mph was recorded at the National Center for Atmospheric Research in Boulder. Heavy damage to power lines…homes…and roads was reported at Evergreen…Golden… And Boulder. Several people were injured by wind-caused accidents. West winds gusted to 53 mph on the 22nd and to 51 mph on the 23rd at Stapleton International Airport where some blowing dust occurred. The Chinook winds warmed temperatures in Denver to highs of 68 degrees on the 22nd and 71 degrees on the 23rd.

Continue reading December 22 to December 28: This Week in Denver Weather History →

Climatology, Thornton Weather

Astronomical winter arrives Saturday, offers up the shortest day of the year

The Winter Solstice
Winter officially begins at 2:21am MST on Saturday, December 21, 2024.

Astronomical winter arrives in Thornton early Saturday morning and with the solstice also comes the shortest day of the year.

Winter officially begins at 2:21am MST on Saturday, December 21, 2024.

The Winter Solstice occurs when the North Pole is tilted at its furthest from the sun – 23.5 degrees away. This results in the shortest day of the year in the Northern Hemisphere.

Here in Denver, with sunrise at 7:17am and sunset at 4:39pm, our day Saturday will be 9 hours, 21 minutes and 15 seconds long.

The following day, Sunday, it will be about three seconds longer and each day from now through to the Summer Solstice in June will get gradually longer as well.

While we have a short day on the solstice, it is nothing like what will be experienced in the Arctic Circle.  Areas north of there to the North Pole will have no direct sunlight at all.  Conversely, areas south of the Antarctic Circle toward the South Pole will have 24 hours of daylight and have a midnight sun.

Did you know that there is a difference between the astronomical seasons that we are discussing here and meteorological seasons?

Meteorological seasons differ slightly and are geared toward matching the calendar with the annual temperature cycle. This is done primarily for meteorological observing and forecasting and in many ways it is more logical than the astronomical seasons.

For the Northern Hemisphere, the meteorological spring covers the months of March, April and May. Summer brings the hottest months of the year and so meteorological summer is June, July and August. Meteorological fall then is September, October and November followed by the coldest months of December, January and February as meteorological winter.

Weather, natural disasters & climate news and information.