Thornton, Colorado, USA
UpdatedFri, 24-Mar-2017 10:00am MDT 


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Santa’s Christmas 2016 journey begins, track online

Saturday, December 24th, 2016 5:45am MDT

ThorntonWeather.com and NORAD offer the Santa TrackerSanta Claus begins his whirlwind trip around the globe tonight to deliver toys to all the good little boys and girls! For more than 50 years the North American Aerospace Defense Command (NORAD) has tracked Kris Kringle on Christmas Eve and helped to ensure he completes his journey safely.

ThorntonWeather.com is pleased to be able to provide live Santa tracking from NORAD right here on our site!

Click here to check it out and be sure to come back often to see where Kris Kringle is at!

Below is the official 2016 NORAD Tracks Santa trailer.

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Holiday weekend to start warm and calm, end cooler and unsettled

Friday, December 23rd, 2016 5:24am MDT

The three-day period will be a bit of a mixed bag with mild, dry conditions Friday and Saturday. Christmas Day brings cooler temperatures, wind, and just a slight chance for snow.

For today we start out with some cloud cover that will gradually ease and give way to mostly sunny to sunny skies above. Overall conditions will be calm as we head toward a high temperature in the mid to upper 40s.

Tomorrow you won’t have any weather worries if you have last minute things to do before the holiday. There will be plenty of sun and we will be dry with highs in the mid-40s.

A coming storm system is going to pass to our west and north Christmas Day limiting its impact but changing things up a bit. We may see just a bit of snow early in the morning but right now it appears snow accumulations will be minimal, if any at all. More notable will be that it will be cooler and winds will be breezy for much of the day.

We wish you and yours a very merry Christmas and a blessed new year!

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Thornton’s Thursday brings chilly temps, slight chance for snow

Thursday, December 22nd, 2016 5:16am MDT

An approaching low pressure system will bring about a bit of a change in our weather today. Colder temperatures and cloudy skies will be the most notable feature with just the slightest chance for a few flakes of snow in the late afternoon and evening.

We start out the day with a healthy dose of cloud cover and that will remain throughout the day. Temperatures will be chilly with highs topping out only in the mid-30s. As the system gets closer, we do see just a slight chance for some snow from about 4:00pm to 9:00pm. At this time, it looks like there will be little, if any at all, accumulation.

Looking ahead, we bounce back to dry conditions and the mid-40s for Friday and Christmas Eve. Christmas Day chills some and does bring just a very slight chance for snow in the morning but right now it doesn’t look particularly likely.

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First day of winter sees cooler temps to near normal

Wednesday, December 21st, 2016 5:10am MDT

A weak front pushed through early this morning giving us some gusty winds that you may have heard. Once its passage is complete, winds will ease and we will be left with a largely seasonal day.

We start out with chilly temperatures although how cold will depend on if those winds continue to warm things up or if they ease before sunrise. After that, look for temperatures in Thornton to gradually warm toward a high right near the average for the date of 42 degrees. Overhead we do expect to see a decent bit of cloud cover.

For more about the winter solstice, see here.

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Astronomical winter to begin Wednesday with the shortest day of the year

Tuesday, December 20th, 2016 11:41am MDT
The Earth at the Winter Solstice. The Northern Hemisphere sees their shortest day of the year while the Southern Hemisphere gets its longest. (NASA)

The Earth at the Winter Solstice. The Northern Hemisphere sees their shortest day of the year while the Southern Hemisphere gets its longest. (NASA)

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

Winter officially begins at 3:44am on Wednesday, December 21, 2016. 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 7:18am and sunset at 4:39pm, our day Wednesday is 9 hours, 21 minutes and 14 seconds long. The day after it will be 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 winter 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.

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Much warmer temperatures, breezy winds for Tuesday

Tuesday, December 20th, 2016 5:39am MDT

Ah yes, the warming effects of downslope winds were very clear this morning and will continue to be through today. Other than a brief dip around 1:00am, we have seen unusually warm mercury readings so far today, all thanks to Chinook winds.

We will be carrying that into the daytime hours when we can expect a high today in the mid-50s, well above the normal of 42 degrees. Those winds will be out of the west and a bit breezy at times, particularly during the first part of the morning and then later in the afternoon. Partly to mostly sunny skies will be above throughout the day.

Keep an eye on the temperature and winds with our live gauges here.

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A white Christmas in Thornton? Chances not great but not bad either

Monday, December 19th, 2016 9:06pm MDT

For many, the holiday season isn’t complete without a chill in the air and snow on the ground. Here in Denver we historically enjoy a better chance of experiencing the proverbial white Christmas than many places in the nation.

However, how the Mile High City fares in experiencing a white Christmas does depend on your definition of one.

If it means having actual snowfall on Christmas Day the chances aren’t that good. But, if simply having snow on the ground suffices, the chances improve considerably.

For a complete look at Denver’s Christmas weather statistics, click here.

Historical Probability of a White Christmas. (NOAA)

Historical Probability of a White Christmas. (NOAA)

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Thornton’s workweek starts with warming temperatures, calm conditions

Monday, December 19th, 2016 5:07am MDT

After three days with temperatures stuck well below freezing, we start to thaw out today. In fact, overall the workweek is going to feature temperatures near or above normal.

For today we start out with clear skies and temperatures in the low single digits. Sunny skies will be the general rule throughout the day with just a few clouds late. Temperatures will be warming to a high close to the normal of 42 degrees for the date.

Looking ahead at our weather for the rest of the week, Tuesday will be the warmest day of the week with the mercury pushing toward 50 degrees. The balance of the workweek should see highs in the low to mid-40s. The next storm system looks to arrive for the weekend and Christmas holiday bringing colder temperatures and a chance for snow.

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December 18 to December 24: This week in Denver weather history

Sunday, December 18th, 2016 8:34pm MDT
This Week In Denver Weather History

December 18 to December 24: This week in Denver weather history

Looking back at Denver weather history, it is readily apparent that the week leading up to Christmas has historically been a very eventful one. There are certainly many of the snow and wind events we would expect to see. Most notable however are the major winter storms like the pre-Christmas storm of 2006 and of course what is arguably Denver’s most famous winter storm, the Christmas Eve Blizzard of 1982.

From the National Weather Service:


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.


In 1901…north winds were sustained to 52 mph with gusts to 58 mph behind an apparent cold front.

In 1973…a brief blizzard dumped heavy snow across metro Denver. Snowfall totaled 9.2 inches at Stapleton International Airport where north winds gusting to 53 mph produced much blowing snow. The storm forced many schools and businesses to close.

In 1996…a homeless man in Denver was found unconscious in his car suffering from exposure. The man’s body temperature was only 85 degrees when he was discovered. He died several hours later. Early morning temperatures had dipped to 9 degrees below zero.

In 1999…high winds were reported for a brief time in the foothills. Winds gusted to 72 mph in Golden Gate Canyon and to 71 mph at the National Center for Atmospheric Research in the foothills southwest of Boulder. West winds gusted to only 39 mph at Denver International Airport where the temperature warmed to a high of 53 degrees.

In 2002…only a trace of snow fell at the site of the former Stapleton International Airport. This…along with the trace of snow on the 5th…was the only snow of the month…ranking the month the 2nd least snowiest on record.

18-19 In 2012…a storm system brought moderate to heavy snow to the mountains and foothills west of metropolitan Denver and blizzard conditions to plains east of Denver metro area. The combination of snow and wind reportedly reduced visibility to just a few hundred feet at times…and resulted in several road closures including Interstate 70 east of Aurora. East of Denver gusty northerly winds ranged from 35 to 55 mph produced extensive blowing and drifting snow…ranging from 1 to 4 feet in depth. Storm totals ranged from 3 to 5 inches. In the mountain and foothills…the heaviest snowfall occurred along and north of I-70 and included: 12 inches at Genesee…9 inches near Eldorado Springs; 8.5 inches at Coal Creek Canyon…8 inches near Evergreen… with 6 inches at Eldora Ski Area…Idaho Springs… Gross Reservoir and Nederland. At Denver International Airport…1.7 inches of snowfall was observed. In addition…a peak wind gust to 35 mph was observed from the north on the 19th.


In 2010…a winter storm produced a 4-day period of moderate to heavy snow in the mountains. The combination of strong wind and heavy snow forced the closure of several mountain passes due to the threat of avalanches. The Amtrak train route… Which runs from Denver to California…was rerouted through Wyoming when Union Pacific closed its tracks along Interstate 70. Numerous accidents forced the closure of I-70 at times. The wind gusted to 60 mph over the higher mountain passes. Storm totals in the ski areas west of Denver ranged from 16 to 32 inches.


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.


In 1913…post-frontal heavy snowfall totaled 8.5 inches over downtown Denver. North winds were sustained to only 16 mph.

In 1994…an intense pacific storm system and associated cold front moved across Colorado early in the day. Strong downslope winds buffeted the Front Range eastern foothills. The highest wind gust recorded was 92 mph at Rocky Flats in northern Jefferson County. Most of the wind gusts during the day ranged from 63 to 86 mph with lighter gusts of 40 to 58 mph on the northeast plains. The strong winds downed power lines and poles in south Lakewood…causing power outages to 2400 homes. Other small power outages and surges occurred across metro Denver. Northwest winds gusted to 43 mph at Stapleton International Airport.


In 1982…high winds buffeted the eastern foothills. At midday on the 19th…gusts of 75 to 80 mph were recorded in the Table Mesa area of Boulder. A gust to 62 mph was clocked in Boulder on the evening of the 20th.

In 1989…strong winds howled at mountain top level in clear creek and Gilpin counties. Speeds reached 97 mph on the summit of Squaw Mountain and 84 mph one mile south of Rollinsville. Northwest winds gusted 35 mph at Stapleton International Airport on the 20th.


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.


In 1894…southwest winds were sustained to 40 mph with gusts to 48 mph. The Chinook winds warmed the temperature to a maximum of 69 degrees…which was a record high temperature for the date. The minimum temperature dipped to only 33 degrees.

In 1903…northwest Chinook winds sustained to 54 mph with gusts to 60 mph warmed the temperature to a high of 58 degrees.

In 1948…strong winds occurred along the eastern foothills from Boulder north. Wind gusts to 45 mph were recorded at Valmont with a gust to 30 mph at Boulder airport. Some damage occurred. Wind gusts to 50 mph caused some blowing dust at Stapleton Airport.

In 1957…strong Chinook winds…gusting to 51 mph from the northwest…warmed the afternoon temperature to a high of 54 degrees.

In 1981 high winds were reported in the foothills with a peak gust of 87 mph recorded at Wondervu.

In 1992…strong Chinook winds raked the eastern foothills with 69 mph recorded at Table Mesa in south Boulder. Southwest winds gusted to only 21 mph at Stapleton International Airport.

In 1996…five construction workers were injured…two seriously…when a sudden wind gust blew over a 30-foot- high retaining wall they were working on in western Lakewood. The scaffolding they were standing on collapsed…and some were pinned under the rubble for 15 minutes. Wind gusts of 60 to 75 mph were reported in the area. Southwest winds gusted to only 24 mph at Denver International Airport.

In 2004…strong downslope winds developed over the eastern mountain slopes and spread over metro Denver. Peak wind gusts approached 100 mph along the foothills of Boulder County. In Superior…a 1200-square-foot section of roof was peeled off the gymnasium at Monarch High School. Two semi-trailers were toppled on Colorado highway 58 at McIntyre Street and another at c-470 and west Bowles Avenue. Two airplanes were damaged by wind-blown debris at Jefferson County Airport. The high winds forced the closure of State Highway 93 between Golden and Boulder for approximately two hours. Insurance agents estimated 650 to 850 homes suffered wind damage in the Boulder and Louisville areas. In addition…downed trees and power lines left about 1000 residents…mainly in the Boulder area…without electricity. At least three people suffered minor injuries in the storm. Peak wind reports included: 95 mph in Superior…92 mph at Jefferson County Airport…85 mph in Golden…81 mph in Boulder…80 mph in Broomfield and Evergreen…and 79 mph in Louisville. West northwest winds gusted to 59 mph at Denver International Airport.


In 1969…high winds caused widespread…but mostly minor damage to roofs…windows…and power lines and overturned some house trailers in areas along and just east of the foothills. Wind gusts of 60 to 70 mph were reported in Boulder and south of Boulder at Rocky Flats. A wind gust to 115 mph was measured in Boulder at the National Center for Atmospheric Research. At Stapleton International Airport…west winds gusted to 44 mph on the 20th and to 45 mph on the 21st. The warm Chinook winds warmed the high temperature to 56 degrees on the 20th and to 65 degrees on the 21st.

In 2006…a major blizzard buried greater metro Denver and the adjacent foothills in deep snow. A slow moving upper level low pressure center produced deep moist upslope flow over the high plains and against the eastern slopes of the mountains…allowing heavy snowfall to persist for 34 hours across metro Denver. Total snow accumulations ranged from 1 to 2 1/2 feet across the city and from 2 to nearly 4 feet in the foothills. Adding to the misery… Strong north winds sustained at 20 to 35 mph with gusts from 45 to nearly 60 mph produced much blowing snow and piled the snow into drifts from 6 to 12 feet high…closing businesses and bringing all transportation to a halt. The storm forced the closure of Denver International Airport for a total of 45 hours which snarled the nation’s air traffic system. This was the longest closure in the airport’s 12 year history. The closure stranded nearly 5000 travelers when 2000 flights were canceled. Many inbound flights were diverted to other airports…stranding even more passengers. Many of the stranded travelers failed to reach their final destinations until days after the airport re-opened due to fully booked flights during the holiday season. Police and national guardsmen rescued hundreds of commuters stuck in their cars…and sent them to temporary shelters set up by the Red Cross. All interstates and other major highways in and out of Denver were closed. Greyhound was forced to cancel all bus trips from Denver. Mail delivery was suspended. The Regional Transportation District suspended all metro Denver bus service for the first time since the March 2003 blizzard. The roof of a discount store in Aurora collapsed under the weight of the heavy snow. In Lakewood…a power outage left 5600 residents without electricity for a brief time. Metro Denver snowfall amounts included: 34 inches 10 miles southeast of Buckley AFB…32 inches in Littleton…30 inches in Thornton and near Castle Rock…29.5 inches near Parker…28 inches in Wheat Ridge…25.5 inches at centennial airport…25 inches at Niwot…24 inches in Aurora…22.5 inches at Greenwood Village… 22 inches in Arvada…21.5 inches in Lakewood…20 inches in Longmont…and 15.5 inches in Boulder. Snowfall measured 20.7 inches officially in the Denver Stapleton area. This ranked the snowfall as the 7th greatest in the city since 1946. North winds were sustained to 37 mph with gusts to 55 mph at Denver International Airport. In the foothills snowfall totaled: 42 inches at Conifer and 11 miles southwest of Boulder…40 inches at Evergreen…39 inches at Aspen Springs… 37.5 inches 8 miles north of Blackhawk…33 inches near Nederland…31 inches at Intercanyon and near Tiny Town…30.5 inches atop Buckhorn Mountain…30 inches near Indian Hills… 29 inches at Rollinsville…24 inches near Gross Reservoir and Ralston Reservoir…22.4 inches atop Crow Hill…and 20 inches near Georgetown. Snowpacked and rutted streets and parking lots persisted for a month or more after the storm and subsequent storms. The heavy snowfall created a snow removal controversy when many citizens complained that residential streets were not cleared in a timely manner in the city and in some suburban areas. This was in spite of the fact that tens of millions of dollars were spent on snow removal. In the city of Denver…snow cover of an inch or more from this storm and subsequent storms persisted for 61 consecutive days…through February 19…2007. This is the second longest period of snow cover on record in the city. Many homeowners who had extensive Christmas lights and decorations in their yards were not able to remove the lights because the wires were buried in deep snow and ice until the end of February or later.

» Click here to read the rest of December 18 to December 24: This week in Denver weather history

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Denver sets record low temperature for December 17

Saturday, December 17th, 2016 8:14pm MDT

Record Cold TemperaturesWe knew it was going to be cold today in the wake of our overnight snow and sure enough, the numbers bear that out.

Denver recorded a low temperature of 15 degrees below zero at 7:14pm.  This easily bests the record low for December 17 of 13 degrees below zero set in 1909.

Here in Thornton, we managed to stay warmer, although with these extremes, that isn’t saying much. Thornton hit a low of 10.7 degrees below zero at 5:57pm.

The storm system brought 5.8 inches of snow to Thornton, our biggest snowfall of the season. Out at DIA where Denver’s official measurements are kept, 8.0 inches fell.

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