Thornton, Colorado, USA
UpdatedSun, 25-Jun-2017 11:20pm MDT 


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Thornton’s Monday starts cold and snowy, some clearing by end of day

Monday, January 16th, 2017 5:25am MDT

We are waking up to a fresh blanket of white this morning. As expected, it didn’t amount to much and it will be ending this morning to be followed by a bit of sun to close things out.

We start out the Martin Luther King, Jr. holiday with snow falling. Roads are slick and slushy so if you venture out early, please allow a bit of extra time. Snow will be coming to an end by mid-morning with only a few snowflakes expected after that.

By noon the cloud cover will start to east slowly and we should see some sun by the end of the day. Temperatures today will be topping out in the mid-30s, a good ways below the average for the day of 44 degrees.

Looking ahead, the balance of the workweek looks to be dry and pleasant with mercury readings at or above normal and lots of sun. See our extended weather forecast for more.

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Cool temps, clouds to be main features of Thornton’s Friday and weekend

Friday, January 13th, 2017 5:11am MDT

Not a particularly great weekend ahead in terms of the weather. A series of systems and fronts is going to ensure steady cloud cover, temps below normal and a chance for snow to close the three-day period out.

For Friday the 13th, a few spots of patchy fog may be seen early then we will be left with mostly cloudy skies above. We will be calm and dry with highs only in the upper 30s. The cloud cover will stay overnight and we will chill down to around 20 degrees.

Saturday looks to be much like today but with temperatures a bit warmer. Partly to mostly cloudy skies will be above as we head for a high in the low 40s. Overnight Saturday night temperatures dip to the mid-20s.

Our next notable system arrives Sunday although its track and timing are still not certain. We do expect plenty of clouds and slightly cooler temperatures. Some light snow / flurries will be possible throughout the day with the best chance for snow coming Sunday evening and through the overnight hours into Monday morning.

Have a great weekend!

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Colder for Thornton Thursday, chance for light snow

Thursday, January 12th, 2017 5:18am MDT

Our weather turns a bit unsettled today. It will be chilly today and this afternoon brings a chance for some snow although it isn’t going to amount to much.

We start the day with mostly clear skies but cloud cover will be building through the morning leaving us with only partly clear skies this afternoon. Temperatures will be starting out a bit below freezing then warming to close to 40 degrees.

Another cold front arrives later and that will help usher in just a chance to see some light snow in the afternoon. Accumulations, if any, are expected to be minimal.

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Mild temps, breezy winds, slight chance for showers Wednesday

Wednesday, January 11th, 2017 5:00am MDT

A good bit of sun and mild temperatures start out the day today. However, a cold front will be moving through later and that means a good bit of wind and just a slight chance for a rain shower in the afternoon.

Mostly sunny skies start things off then by late morning a few more clouds will appear above. Temperatures will climb to a high in the mid-50s by noon then the mercury will descend steadily in the afternoon.

There will be enough instability with the front to create the potential for a few rain showers along the Front Range. Right now it doesn’t appear that this would amount to much, if at all. You can keep an eye out for those showers with our weather radar here.

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Tuesday brings cooler temps, more wind

Tuesday, January 10th, 2017 4:55am MDT

With the passing of a weak cold front late yesterday, cooler temperatures will be the rule today although readings will still be above normal. Winds will again be quite breezy.

We start out the day with mostly clear skies and will see similar sky conditions throughout the day. Temperatures will top out right around the 50 degree mark, maybe a couple of degrees above.

Look for winds to build later this morning and peak by early to mid-afternoon with gusts to 30+ mph being possible. They will then slowly ease but remain breezy into tonight.

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Thornton’s workweek starts very mild but with a good bit of wind

Monday, January 9th, 2017 5:13am MDT

Today we will feel the effects of Chinook winds. While they will provide a great deal of warming, they also will create blustery conditions outside.

We start out this morning quite mild as winds started picking up around 3:00am and the resultant warmth drove the mercury higher. Temperatures will be topping out today in the low 60s, well above the average of 44 degrees for the date.

Winds are going to continue to build in intensity through early afternoon and then gradually begin to taper off before becoming calm around midnight. Gusts to 45 mph or so will be possible at their peak.

Keep an eye on the temperature and wind speeds here.

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January 8 to January 14: This Week in Denver Weather History

Sunday, January 8th, 2017 4:32am MDT
This Week In Denver Weather History

January 8 to January 14: This Week in Denver Weather History

January in Colorado is known for two main weather conditions – cold and wind. Our look back at this week in Denver weather history shows why this reputation is well earned.

From the National Weather Service:


In 1911…gale force winds occurred in Boulder causing minor injuries.

In 1937…cold arctic air plunged temperatures below zero for an estimated 56 consecutive hours. Two temperature records were set. High temperatures of 8 degrees below zero on the 7th and 3 degrees on the 8th were record low maximum readings for those dates. Low temperatures plunged to 12 degrees below zero on the 7th and 11 degrees below zero on the 8th. Snowfall was 1.4 inches in downtown Denver.

In 1969…a violent evening windstorm struck Boulder and the adjacent foothills. A wind gust to 130 mph was recorded at the National Center for Atmospheric Research. Winds reached 96 mph in downtown Boulder. The Boulder airport wind recorder was blown away after measuring a wind gust to 80 mph. The windstorm caused over one million dollars in damage and one fatality in Boulder. About 25 homes in south Boulder had roofs blown off or were severely damaged. Roofs were blown off buildings housing scientific laboratories and offices of the Environmental Science Services Administration…now NOAA…in Boulder…and installations of several scientific measuring sites near Boulder received heavy damage. Grass fires driven by the high winds endangered many areas…but were controlled by volunteer firemen. One man died from injuries received when he was blown from a fire truck. One man was killed and another injured when the truck camper in which they were riding was blown off I-25 about 10 miles north of Denver. In the same area a mobile home and a truck trailer were blown off the highway and demolished. At least 20 people in the Boulder area received light to serious injuries from flying debris or from being blown into obstructions. Power lines and trees were downed over a wide area. Damage was relatively light in the city of Denver…where northwest winds gusted to 62 mph at Stapleton International Airport on the 8th. Many windows were broken in Arvada…Englewood…and Littleton. A 27-year-old fire lookout tower on Squaw Mountain…west of Denver…was blown away…and several radio relay towers at that location were toppled. Trucks were overturned near Georgetown. Mobile homes were overturned in several areas with occupants receiving injuries in some cases. The strong Chinook winds also brought warm weather. The maximum temperature of 69 degrees on the 7th broke the old record of 65 degrees set in 1948. The temperature also reached 65 degrees on the 8th…but was not a record.

In 1992…an intense blizzard buried eastern parts of metro Denver. At times snow fell at rates of 2 to 3 inches an hour. Winds increased from the north at speeds of 25 to 45 mph. Drifts of 4 to 8 feet were common. I-70 was closed east of Denver…and I-25 was closed from Denver south. Snowfall totals ranged from a couple of inches in the foothills west of Denver to as much as 2 feet on the east side of metro Denver. The heaviest snow fell on the 7th in a band from the northern suburbs of Westminster and Thornton through Aurora and east Denver to southeast of Parker. Snowfall totals included: 22 inches in southeast Aurora…14.8 inches at Stapleton International Airport…13 inches in Northglenn…10 inches in Parker…and 9 inches in Westminster. The 14.5 inches of snowfall measured on the 7th into the 8th is the greatest 24 hour snowfall ever recorded in the city during the month of January. North winds gusting to 46 mph caused much blowing snow at Stapleton International Airport.

In 2000…high winds developed in and near the Front Range foothills. The strongest winds were generally confined to foothills areas north of I-70. A wind gust to 76 mph was reported in Golden Gate Canyon. West winds gusted to 37 mph at Denver International Airport on the 8th.


In 1962…a major winter storm dumped 13.5 inches of snow on metro Denver. A foot of the snow fell on the 8th when northeast winds gusted to 30 mph. The storm was followed by an intense blast of very cold arctic air. Minimum temperature readings of 24 degrees below zero occurred on both the 9th and 10th. The temperature never reached above zero on the 9th when a maximum reading of 1 degree below zero was recorded. Temperatures were below zero for 37 consecutive hours.


In 1912…northwest winds were sustained to 40 mph with gusts to 45 mph in downtown Denver.

In 1971…wind gusts to 52 mph were recorded in downtown Boulder. Northwest winds gusted to 28 mph at Stapleton International Airport.

In 1990…high winds gusting from 50 to 90 mph along the Front Range produced much damage from blowing dust and gravel throughout the day. Wind gusts to 92 mph were recorded in the Table Mesa area of southwest Boulder. The winds caused sporadic power outages. Clouds of dust and gravel whipped by 70 to 90 mph gusts blinded commuters on the Denver-Boulder Turnpike near Broomfield during the morning rush hour. Flying gravel shattered windows on 50 vehicles parked near a Boulder high school. High winds were also blamed for partially dismantling a house under construction in Boulder…as well as toppling a number of fences…billboards…signs…and power poles. The strong cross-winds jack-knifed and overturned semi-tractor trailers on I-70 near Golden and just south of Boulder on State Highway 93. Several county airports were closed due to strong winds and blowing dust reducing visibilities. Wind delays up to 30 minutes occurred at Stapleton International Airport where west winds gusted to 48 mph. Eighty mph winds in Georgetown…Empire…and Idaho Springs were blamed for power and telephone outages. Windows were blown out of a sheriff’s car along I-70 east of Georgetown. The strong Chinook winds warmed the temperature to a high of 60 degrees in Denver.

In 2007…strong winds associated with an intense upper level jet…and a very strong surface pressure gradient…developed in and near the Front Range foothills. Peak wind gusts ranged from 77 mph to 115 mph. The strong winds coupled with freshly fallen snow resulted in whiteout conditions and several highway closures due to blowing and drifting snow. Road closures included: State Highway 93 between Golden and Boulder; State Highway 128 from Wadsworth Boulevard to State Highway 93; U.S. Highway 36…the Denver Boulder Turnpike from Broomfield to South Boulder Road; and State Highway 74 near Evergreen…between County Road 65 and Lewis Ridge Road. More than 100 people were stranded in their cars between Golden and Boulder as blowing and drifting snow made the highway impassable. Snow drifts along State Highway 93 were over 6 feet in depth. As a result… The American Red Cross opened a shelter at Arvada West High School for the stranded commuters. Up to twenty cars were also abandoned along the Diagonal Highway…between Boulder and Longmont. Thirty vehicles were stranded along State Highway 128. The high winds also caused intermittent power outages in Boulder. West winds gusted to 40 mph at Denver International Airport


In 1891…heavy dry snowfall totaled 9.7 inches over downtown Denver. Most of the snow…6.5 inches…occurred on the 8th when north winds were sustained to 12 mph with gusts to 20 mph.

In 1939…heavy snowfall totaled 6.7 inches in downtown Denver. The snowfall was the heaviest overnight…particularly during the early morning hours. The moist snow adhered to the north side of the instrument shelter and other objects to a depth of 2 inches. Snow accumulated on fences and trees to several inches. This was the greatest snowfall of the month that year. The greatest depth on the ground was 6.5 inches. North to northwest winds were sustained to 24 mph on the 8th and to 27 mph on the 9th.


In 1983…winds of 70 to 90 mph howled through Boulder. A wind gust to 100 mph was recorded on Fritz Peak near Rollinsville. A tree blown down by the wind damaged a house in eastern Boulder County. The strong winds developed behind a cold front late on the 8th and continued through the 10th. At Stapleton International Airport…west to northwest winds gusted to 49 mph on the 8th…to 45 mph on the 9th…and to 48 mph on the 10th.


In 1875…the all time lowest recorded official temperature in Denver…29 degrees below zero…occurred between 3:00 am and 4:00 am under clear skies with calm winds. The temperature climbed to zero at noon and to a high of 8 degrees at 3:00 pm.

In 1916…Chinook winds from the southwest sustained to 42 mph with gusts as high as 48 mph warmed the temperature to a high of 57 degrees.

In 1917…Chinook winds…southwesterly in direction…sustained at 43 mph with gusts to 48 mph warmed the temperature to a high of 55 degrees. The low temperature was only 43 degrees.

In 1950…strong west winds to 50 mph produced blowing dust… Which briefly reduced visibility to 3/4 mile at Stapleton Airport.

In 1957…west-northwest winds gusted to 51 mph at Stapleton Airport.

In 1988…a wind gust to 61 mph was recorded at Echo Lake. West winds gusted to only 16 mph at Stapleton International Airport.

In 1989…strong Chinook winds howled along the eastern foothills. A peak gust to 115 mph was recorded at the Boulder airport where a light plane was severely damaged when the wind flipped it over. Gusts reached 103 mph at Table Mesa in south Boulder. Homes in the city suffered damage to roofs…gutters…and siding. Fences were blown down…and windows in both homes and cars were broken. A radio station was off the air for 2 1/2 hours when the winds blew the top 80 feet off its 180-foot transmission tower. A school roof was partially torn off…and a few traffic signals were downed. Winds 60 to 80 mph were reported at Jefferson County Airport in Broomfield. West winds gusted to 47 mph at Stapleton International Airport.

In 1990…high winds buffeted the Front Range foothills for a second straight day. Wind gusts to 92 mph were recorded at Rollinsville. Wind gusts of 65 to 90 mph were noted in the Denver-Boulder area. No significant damage occurred. Northwest winds gusted to 38 mph at Stapleton International Airport where the maximum temperature reached 63 degrees.


In 1962…the low temperature plunged to 24 degrees below zero on both days.

In 1972…a west wind gust to 60 mph was recorded at Stapleton International Airport…while in Boulder a wind gust to 86 mph was recorded at the National Bureau of Standards. The roof of a house was blown off…and trees were blown down in Boulder. The high winds contributed to the damage from a building fire in Boulder.

In 2000…heavy snow and strong winds in the mountains spilled into the Front Range foothills. Ward…northwest of Boulder…received 9 inches of new snow. Wind gusts to 91 mph were measured in Golden Gate Canyon…with gusts to 77 mph at Loveland Ski Area and to 73 mph along State Highway 93 north of Golden. West winds gusted to 44 mph at Denver International Airport on the 9th.

In 2011…a winter storm brought moderate to heavy snowfall to areas in and near the Front Range foothills and Palmer Divide. Storm totals included: 13 inches…3 miles south of Golden; 11.5 inches near Eldorado Springs…10.5 inches… 2 miles southwest of Boulder; 10 inches…3 miles southwest of Roxbourough State Park; 9 inches at Genesee…8.5 inches in Arvada…4 miles south-southeast of Bennett and Greenwood Village…8 inches…8 miles south of Elizabeth; 7 inches at Commerce City and 6.5 inches near Louisville and at Denver International Airport. Gusty winds produced snow drifts up to 2 feet deep over the Palmer Divide.

» Click here to read the rest of January 8 to January 14: This Week in Denver Weather History

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Thornton’s weekend weather starts chilly, will end mild

Friday, January 6th, 2017 5:12am MDT

You woke up this morning to some bone-chilling temperatures a good ways below zero degrees. The good news is that there will be some warming today and by the time the end of the weekend we should see readings above normal.

For today we start out extremely cold and then will be warming to a high in the low to mid-20s. Look for a healthy dose of sun above and calm, dry conditions. Overnight tonight we dip down into the single digits.

After the cold start Saturday morning, temperatures will start climbing and come close to the freezing mark. Sunny to mostly sunny skies will be above. Overnight lows Saturday night into Sunday morning will drop to the teens.

We close out the weekend with the warmest day of the period Sunday. There should be plenty of sun as we climb toward a high expected to reach around 50 degrees. Models would indicate that kind of warmth but we admit to having our doubts given the amount of snow cover. We will see but either way it will be warmer.

Have a great weekend!

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Time lapse video: Thornton’s first snowstorm of 2017

Thursday, January 5th, 2017 7:00pm MDT

Mother Nature seems intent on starting out 2017 the way she ended 2016 – cold.  A deep trough coupled with successive, reinforcing cold fronts sent Thornton’s mercury plunging and delivered a healthy shot of snow over the last couple of days.

Below is a time lapse video from our east webcam covering the majority of the event. It begins at 6:00am on Wednesday, January 4 when we were only seeing flurries.  From there you see the varying intensities of snow over the next 24 hours or so and end with some hints of blue sky but the afternoon of the 5th. In all, the video covers 36 hours in about 83 second.

Thornton ended with 7.1 inches of snow over the two-day period, our biggest snowfall of the season thus far.

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December 2016 weather recap: A colder, wetter month finally arrives

Thursday, January 5th, 2017 12:56pm MDT

For the three previous months we had seen warmer and drier than normal conditions.  December finally brought an end to that streak with temperatures well below normal and precipitation almost doubt the average for the month.

The month was largely an unsettled one as a series of storm systems moved across the region.  Two significant blasts of Arctic air sent the mercury plummeting.  The first, from the 6th to the 8th, brought little snowfall but the second from the 16th to the 18th was quite generous.  The balance of the month saw things warm up with 10 of the last 13 days seeing above normal mercury readings.

Overall, Thornton saw an average monthly temperature of 28.1 degrees.  This was well below Denver’s 30 year average (1981 – 2000) for the month of December of 30.0 degrees.  Out at DIA where the Mile High City’s official measurements are taken, the month averaged 27.8 degrees.

Temperatures ranged from a high of 65.7 degrees on the 30th down to a bone-chilling low of 10.7 degrees below zero on the morning of the 17th.  Denver saw its warmest temperature of 65 degrees and coldest of 15 degrees below zero on the same dates.

That low reading in Denver on the 17th was also a record low for the date.  Additionally, the airport saw a high temperature of only 3 degrees that day setting a new record low maximum for the 17th.

In all, Thornton saw five days where the high temperatures failed to climb above freezing and four days with temperatures below zero.  Denver recorded six and four respectively.

In terms of precipitation, Denver averages 0.35 inches of liquid precipitation during December.  Thornton easily bested the average with 0.64 inches for the month while Denver fared better with 0.78 inches.

Both Thornton and Denver saw above average levels of snowfall.  The Mile High City averages 8.5 inches in December. In 2016, Thornton saw 8.9 inches while DIA recorded 9.7 inches.

Click here to view Thornton’s December  2016 climate report.

Thornton, Colorado's December 2016 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2016 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's December 2016 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2016 precipitation summary. (ThorntonWeather.com)

From the National Weather Service:

718 AM MST SUN JAN 1 2017




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              79   12/05/1939
 LOW              -25   12/22/1990
HIGHEST            65   12/30        43      22       69  12/09
LOWEST            -15   12/17        17     -28        0  12/28
AVG. MAXIMUM     42.7              42.8    -0.1     40.9
AVG. MINIMUM     12.9              17.1    -4.2     17.9
MEAN             27.8              30.0    -2.2     29.4
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      6               5.8     0.2       10
DAYS MIN <= 32     30              29.4     0.6       28
DAYS MIN <= 0 4 2.0 2.0 2 PRECIPITATION (INCHES) RECORD MAXIMUM 5.21 1913 MINIMUM 0.00 1881 TOTALS 0.78 0.35 0.43 0.71 DAILY AVG. 0.03 0.01 0.02 0.02 DAYS >= .01         6               4.1     1.9        5
DAYS >= .10         2               1.1     0.9        3
DAYS >= .50         0               0.1    -0.1        0
DAYS >= 1.00        0               0.0     0.0        0
 24 HR. TOTAL    0.63   12/16 TO 12/17

TOTALS            9.7   2016        8.5 NORMAL
RECORDS          57.4   1913
                    T   1905 1906 2002

HEATING TOTAL    1146              1086      60     1097
 SINCE 7/1       2042              2468    -426     2187
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        878               769     109      877

 EARLIEST     09/08/1962        10/07
 LATEST       06/08/2007        05/05

AVERAGE WIND SPEED              9.2

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            7
NUMBER OF DAYS PC             18


THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                0     RAIN                       0
LIGHT RAIN                1     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                2     SNOW                       3
LIGHT SNOW                7     SLEET                      0
FOG                      11     FOG W/VIS <= 1/4 MILE      3
HAZE                      6

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