Thornton, Colorado, USA
UpdatedMon, 23-Apr-2018 8:30pm MDT 


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Thornton’s weekend to offer dry, warmer than normal conditions

Friday, January 12th, 2018 5:05am MDT

An uneventful weekend of weather for us. Friday will see some wind but other than that, conditions will remain mild and we should generally have a good bit of sun throughout the period.

For today, a pressure gradient will give rise to some breezy conditions for much of the day. Skies above will be partly sunny. Look for highs today around the 50 degree mark, perhaps a bit warmer. Tonight, partly cloudy skies will be above with lows dipping well into the 20s.

Tomorrow will be just a bit cooler but with less wind and more sun. Mostly sunny skies will be above with highs in the upper 40s. Saturday night into Sunday morning partly cloudy skies will be above, lows dip into the mid-20s.

We close out the weekend on Sunday with the nicest day of the period. Expect to see a healthy dose of sun above, high temperatures in the mid-50s.

Beyond that, we do see things changing for Monday as a front moves in Sunday night. This will bring colder temperatures and a chance for snow on Martin Luther King, Jr. Day.

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Calm, dry but a bit chilly for Thornton’s Thursday

Thursday, January 11th, 2018 5:01am MDT

Yesterday brought some much-needed precipitation but it didn’t amount to much and we are still far behind from what we normally see by now in the season. Today, we return to the dry conditions although temperatures will remain on the chilly side.

The day starts with a few clouds but those will quickly clear leading to sunny skies for much of the day. Winds will be light and out of the west. Temperatures will top out around the 40 degree mark.

Tonight, clouds will increase and we will see lows in the mid-20s.

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Wednesday starts warm, afternoon and evening bring chance for showers

Wednesday, January 10th, 2018 5:09am MDT

A bit of a change in the weather pattern for Thornton today. The day starts out relatively nice and will see above normal highs however an approaching system will give us a chance for much-needed precipitation later in the day and into tonight.

Partly clear skies start things off but we will then see a gradual increase in cloud coverage as moisture aloft increases. Temperatures start out cool then warm toward a high in the mid-50s. As the cold front arrives this afternoon, mercury readings will begin a steady drop. Winds will initially be calm but again, with the front coming, pick up speed in the late afternoon into the first half of tonight.

As for precipitation, light rain becomes a possibility after noon. After the sun goes down and temperatures drop, a change to snow will become possible. While the moisture is welcome, we unfortunately just are not expecting much out of this system – just enough to get things damp. Little or no accumulation of snow is expected.

Tonight, the snow will be pretty much done by 9:00pm with only a few lingering flakes possible till midnight. Then, skies will clear leading to overnight lows in the mid-20s.

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Tuesday to bring very mild temperatures, return of the sun to Thornton

Tuesday, January 9th, 2018 5:07am MDT

You sure won’t be thinking it is mid-January with today’s weather and we are going to enjoy a day with temperatures nearly 20 degrees above normal.

The day starts off with mostly clear skies and we should see similar conditions above throughout the day. There will be some cloud coverage but nothing overly intrusive. Winds will be light and out of the southwest.

As for those temperatures, we will see a steady climb in them this morning heading toward an afternoon high around the mid-60s. Average for the date is 44 degrees.

Tonight, look for mostly cloudy skies with lows in the mid to upper 30s.

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Thornton’s workweek starts with mild temps, a good bit of cloud cover

Monday, January 8th, 2018 5:08am MDT

Our weather today looks to be not entirely unlike what we have seen the last few days. Temperatures will once again be above normal although we do expect to see a good bit of cloud cover.

The day starts with mostly clear skies then as moisture builds aloft, cloud coverage will increase. Partly sunny skies will be the rule for most of the day. Winds will be light, conditions calm. Temperatures should warm to a high in the low to mid-50s however if the cloud cover is thick, it could suppress the mercury a bit below that.

Tonight, mostly cloudy skies will be above with lows in the low to mid-30s.

What lies ahead for the rest of the week? Find out here.

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January 7 to January 13: This Week in Denver Weather History

Monday, January 8th, 2018 4:14am MDT
This Week In Denver Weather History

January 7 to January 13: 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 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.


In 1908…furious high winds were noted in Boulder but caused only minor damage and injury.

In 1913…a very cold arctic air mass caused temperatures to plunge to record levels. The low temperature fell to 21 degrees below zero on the 6th and to 18 degrees below zero on the 7th…both records. The high temperature of only 8 degrees below zero on the 6th was a record low maximum for the date.

In 1920…post-frontal heavy snowfall totaled 7.0 inches in downtown Denver. North winds were sustained at 24 mph with gusts to 30 mph on the 6th.

In 1923…warm Chinook winds resulted in two temperature records. Low temperatures of 37 degrees on the 6th and 42 degrees on the 7th equaled the record high minimums for the dates. West winds were sustained to 30 mph with gusts to 33 mph on the 6th. Southwest winds were sustained to 47 mph with gusts to 52 mph on the 7th. High temperatures were 53 degrees on the 6th and 56 degrees on the 7th.

In 1986…2 to 4 inches of snow fell over metro Denver… With 5 to 8 inches in the foothills west of the city. The 2.4 inches of snowfall recorded at Stapleton International Airport was the only snowfall of the month. Northwest winds gusted to 24 mph at the airport.

In 2006…a brief warm spell resulted in two temperature records. High temperatures of 66 degrees on the 6th and 69 degrees on the 7th equaled the record daily maximum temperatures for each of those days. Low temperatures remained above freezing and were within 1 or 2 degrees of the record daily high minimums.


In 1911…west Chinook winds were sustained to 51 mph and warmed the temperature to a high of 56 degrees.

In 1994…occasional high winds buffeted the eastern foothills. Wind gusts to 99 mph were recorded at Rollinsville…southwest of Boulder. West winds gusted to 40 mph at Stapleton International Airport.

In 1995…a brief blast of high winds hit the eastern foothills and adjacent Front Range communities. A wind gust to 112 mph was recorded atop Squaw Mountain…west of Denver. In Boulder…winds gusted to 81 mph. West winds gusted to 31 mph at Stapleton International Airport.

In 2009…damaging downslope winds were responsible for triggering two wildfires that threatened the city of Boulder. Peak wind gusts ranged from 75 to 107 mph in and near the foothills of Boulder…Jefferson and park counties. Although the fires never merged…they were close enough for firefighters to build a perimeter around both of them. The fires quickly torched 3000 acres and forced the evacuation of up to 1400 families. One home was destroyed along with several barns and outbuildings. Three firemen suffered minor injuries. In Bailey…power lines were downed by falling trees. A tin roof on an auto repair shop in town was almost completely blown off. Peak wind gusts included: 107 mph…3 miles south of Mt. Audobon…92 mph…3 miles south of Evergreen; 87 mph…6 miles northwest of Boulder; 81 mph…2 miles east-northeast of Bergen Park and at the National Wind Technology Center; 79 mph…4 miles northeast of Nederland; 77 mph…3 miles west of Sheridan; 75 mph at Genesee. A peak wind gust of 39 mph was measured at Denver International Airport from the west.


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.

» Click here to read the rest of January 7 to January 13: This Week in Denver Weather History

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Al Gore under fire for climate change claim on bomb cyclone icy storm

Sunday, January 7th, 2018 7:26am MDT

Former Vice President Al Gore is taking heat for his claim that the icy nor’easter blanketing the eastern seaboard with snow and freezing temperatures is “exactly what we should expect from the climate crisis.” » Click here to read the rest of Al Gore under fire for climate change claim on bomb cyclone icy storm

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First weekend of 2018 to keep things mild, bring one chance for showers

Friday, January 5th, 2018 4:34am MDT

Overall a pretty nice looking weekend ahead for Thornton in terms of the weather. Temperatures will be above normal throughout the period with only one slight chance for showers overnight Saturday night.

With increased moisture aloft, we will see a bit of cloud cover on Friday. Temperatures however won’t be inhibited much by them with highs still expected to reach the mid-50s.

Tonight, partly cloudy skies will remain above with lows in the upper 20s.

Saturday looks to be much like today with similar amounts of cloud coverage. High temperatures will increase a few degrees.

A passing system introduces a chance for some isolated shower activity overnight Saturday into the pre-dawn hours Sunday. We are not expecting much out of this however.

Sunday won’t see many lingering effects from the system. Mostly sunny skies will be above with highs near the 50 degree mark.

Have a great weekend!

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December 2017 recap: Despite cold finish, month was warmer and drier than average

Thursday, January 4th, 2018 9:16am MDT

With the last part of December fresh in our minds, it would not be surprising to think of the month as a cold one. However, reaching back, if you recall, we actually enjoyed a lot of mild days earlier and very little precipitation. As a result, December 2017 goes into the books as a warm and dry one.

The first half of the month was notable for stable conditions yielding above normal temperatures and no precipitation. Denver set a record high temperature on the 12th of 69 degrees which was also our warmest reading of the month.

Not long after the warmth came the cold.  Arctic air infiltrated from the north on the 21st resulting in much cooler temperatures and a pre-Christmas snow. This was followed by another snow on the 23rd that lasted into the early morning hours of Christmas Eve. Single digit lows were seen for seven days from the 21st to the 27th.

We then saw a brief warmup for the 27th to the 29th but that was short lived. We closed out the month with the final two days’ high temperatures failing to reach even the freezing mark.

On average, Denver’s temperature for December comes in at 30.0 degrees.  Both Thornton and the Mile High City came in above that with average readings of 31.8 degrees and 33.2 degrees respectively.

Thornton saw its warmest temperature reading of 69.1 degrees on the 12th and its coldest of 1.6 degrees on the morning of the 27th.  Denver’s warmest reading of 69 degrees also came on the 12th and its coldest of -4 degrees came on the 24th.

In terms of precipitation, Thornton saw a mere 0.16 inch of liquid in its bucket for the month. Denver was a bit better with 0.21 inches. Both were below the long-term Denver average of 0.35 inches.

December on average brings 8.5 inches of snowfall to Denver.  Thornton fell well short of that with 4.7 inches and Denver just a bit less with 4.0 inches.

Click here to view Thornton’s December 2017 climate report.

Thornton, Colorado's December 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2017 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's December 2017 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s December 2017 precipitation summary. (ThorntonWeather.com)

645 AM MST MON JAN 1 2018




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              79   12/05/1939
 LOW              -25   12/22/1990
HIGHEST            69   12/12        62       7       65  12/30
LOWEST             -4   12/24        -4       0      -15  12/17
AVG. MAXIMUM     48.3              42.8     5.5     42.7
AVG. MINIMUM     18.0              17.1     0.9     12.9
MEAN             33.2              30.0     3.2     27.8
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      4               5.8    -1.8        6
DAYS MIN <= 32     28              29.4    -1.4       30
DAYS MIN <= 0       1               2.0    -1.0        4

 MAXIMUM         5.21   1913
 MINIMUM         0.00   1881
TOTALS           0.21              0.35   -0.14     0.78
DAILY AVG.       0.01              0.01    0.00     0.03
DAYS >= .01         4               4.1    -0.1        6
DAYS >= .10         1               1.1    -0.1        2
DAYS >= .50         0               0.1    -0.1        0
DAYS >= 1.00        0               0.0     0.0        0
 24 HR. TOTAL    0.10   12/23 TO 12/23
 STORM TOTAL     0.10   12/23 TO 12/23

 TOTAL           57.4   1913
TOTALS            4.0   2017        8.5

HEATING TOTAL     979              1086    -107     1146
 SINCE 7/1       2150              2468    -318     2042
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        881               769     112      878

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

AVERAGE WIND SPEED              10.0

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            8
NUMBER OF DAYS PC             18

AVERAGE RH (PERCENT)          49

FOG OR MIST                   12
FOG VSBY LESS 1/4 MI           4
THUNDER                        0
ICE PELLETS                    0
HAIL                           0
DUST STORM                     0
SMOKE OR HAZE                  5
BLOWING SNOW                   0
TORNADO                        0

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Thornton’s Thursday weather to bring unseasonably warm temps, lots of sun

Thursday, January 4th, 2018 4:57am MDT

A very pleasant winter day ahead for us. Look for plenty of sun and temps about 10 degrees above normal.

The day starts with a bit of cloud cover but that will quickly dissipate bringing sunny skies by mid-morning. Winds will be light and out of the south, conditions dry. Temperatures will climb nicely and top out in the low 50s.

Tonight, mostly clear skies will be above will lows dipping to the low to mid-20s.

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