Thornton, Colorado, USA
UpdatedThu, 30-Mar-2017 6:40am MDT 


ThorntonWeather.com on Twitter

ThorntonWeather.com on Facebook


Weather Geek Stuff - weathergeekstuff.com

Rocky Mountain Weather Network

Tony's Takes Photography


Recent News and Posts

Thornton’s workweek starts with a seasonal, pleasant day

Monday, December 12th, 2016 5:36am MDT

As we head back to work for the week we are going to enjoy a nice, late fall day. Temps will be a bit above normal, there will be plenty of sun and the only potential hiccup will come in the form of some breezy winds this afternoon.

We start out the day under mostly clear skies and similar conditions above will remain. A few spots may be seeing some fog early but those will burn off quickly once the sun comes up. Temperatures will be climbing toward a high in the mid-40s, a bit above the average for the date of 42 degrees. This afternoon will bring some gusty winds.

Have a great Monday!

Join the Discussion - Post your commentJoin the Discussion!

December 11 to December 17: This Week in Denver Weather History

Sunday, December 11th, 2016 6:00pm MDT
This Week In Denver Weather History

December 11 to December 17: This Week in Denver Weather History

This time of year snow is a common occurrence but in our look back at this week in Denver weather history we are struck by the lack of significant snow events in the history books for the period. What we do see instead are a number of high wind events, many of which caused widespread damage.

From the National Weather Service:


In 1939…more than 2 weeks of unseasonably warm weather made the month the 3rd warmest on record. Seven daily temperature records were set…including the all time record high temperature for the month of 79 degrees on the 5th. Daytime highs were balmy with 14 days in the 60’s and 70’s. Low temperatures dipped to freezing or below on only 5 days. The period was dry with only a trace of snow on the 12th.


In 1972…a protracted cold spell held an icy grip on metro Denver when maximum temperatures never reached above freezing for 10 consecutive days from the 3rd through the 12th and minimum temperatures dipped below zero on eleven consecutive days from the 5th through the 15th. Daily low temperature records were set with 15 degrees below zero on the 5th…17 degrees below zero on the 6th… And 18 degrees below zero on the 10th. Daily record low maximum readings were set with 3 degrees on the 6th and 6 degrees on the 9th. The very cold temperatures were caused by 3 to 5 inches of snow cover and a Canadian air mass.


In 1932…the second longest sub-zero period on record in Denver occurred. The temperature fell below zero shortly after 1:00 pm on the 8th and remained below zero for 92 hours until 9:00 am on the 12th. The lowest temperature recorded during this period was 13 degrees below zero on both the 9th and 11th. That temperature on the 11th was a record low for the date. High temperatures of 4 on the 8th…5 below zero on the 9th…1 below zero on the 10th… And 6 below zero on the 11th were record low maximum temperatures for those dates. Light north winds at 5 to 10 mph were accompanied by occasional light snow…which totaled only 2.2 inches.


In 1961…cold arctic air produced a protracted cold period. The temperature plunged to 16 degrees below zero on the 10th…establishing a new record for the date and the coldest reading since 25 degrees below zero on February 1… 1951. Low temperatures dipped below zero on 5 consecutive days with 9 degrees below zero on the 9th…16 below on the 10th…10 below on the 11th…and 12 below on both the 12th and 13th. High temperatures reached only 3 degrees on the 10th and 6 degrees on the 11th.


In 1933…downslope winds produced warm temperatures…resulting in record high minimums of 46 degrees on the 10th and 44 degrees on the 11th. High temperatures of 66 degrees on the 10th and 62 degrees on the 11th were not records. Southwest winds were sustained to 16 mph on the 10th.

In 1939…high temperatures of 70 degrees on the 10th and 74 degrees on the 11th were record maximums for the dates. The low temperatures of 39 degrees on the 10th and 41 degrees on the 11th were not records.

In 1948…high winds in Boulder and Louisville caused 1750 dollars in damage. Wind gusts in excess of 70 mph were reported at Valmont and Boulder airport. Chinook wind gusts to 60 mph briefly reduced the visibility to 1/4 mile in blowing dust at Stapleton Airport.

In 1989…the season’s greatest snowfall to date hit metro Denver with 6 to 12 inches of snow. Flight delays at Stapleton International Airport reached 2 hours. Multiple wrecks snarled traffic on I-25 both north and south of the city. Snowfall totaled 7.0 inches at Stapleton International Airport where north winds gusted to 25 mph on the 10th.


In 1938…snowfall totaled 3.7 inches in downtown Denver. North winds were sustained to 21 mph with an extreme velocity to 22 mph.

In 1967…wind gusts to 58 mph in downtown Boulder caused minor damage. Northwest winds gusted to 47 mph at Stapleton International Airport.

In 1980…winds to 60 mph were reported in Boulder. Northwest winds gusted to 23 mph at Stapleton International Airport. The Chinook winds warmed temperatures to a high of 67 degrees.

In 1994…strong gusty winds occurred along the Front Range eastern foothills. A wind gust to 67 mph was recorded in Boulder with a gust to 58 mph measured at Jefferson County Airport near Broomfield. No damage was reported. Northwest winds gusted to 31 mph at Stapleton International Airport.


In 1903…a sharp cold front on the 11th plunged temperatures from a high of 59 degrees to a low of 15 degrees…produced northeast winds sustained to 42 mph along with gusts as high as 60 mph…and produced 1.3 inches of snow overnight. The high temperature on the 12th was only 25 degrees.

In 1968…strong winds buffeted the eastern foothills and plains and caused light…but widespread property damage. Wind gusts of 50 to 75 mph were reported. West winds gusted to 52 mph at Stapleton International Airport.


In 1940…5.4 inches of snow fell across downtown Denver. This was the only snowfall of the month. Temperatures were quite cold on the 13th with a high of 6 degrees and a low of 2 degrees below zero.

In 1984…up to 6 inches of new snow fell over metro Denver… Hampering flight operations at Stapleton International Airport where snowfall totaled 3.8 inches and east winds gusted to 25 mph on the 11th.


In 1937…a thunderstorm…rare in December…produced 0.09 inch of rain in advance of a cold front.

In 1973…high winds occurred across all of metro Denver with the foothills area being hit the hardest. A wind gust to 120 mph was recorded in Boulder where damage to residences…mobile homes…fences…and buildings totaled 100 thousand dollars. A northwest wind gust to 66 mph occurred at Stapleton International Airport.

In 1988…strong winds were recorded in Boulder. Peak wind gusts reached 70 mph at Table Mesa and 61 mph in east Boulder. West winds gusted to 31 mph at Stapleton International Airport.


In 1916…snowfall totaled 5.7 inches in downtown Denver. Northeast winds were sustained to 27 mph with gusts to 28 mph on the 12th.

In 1992…an upslope snowstorm whitened metro Denver. While snowfall totaled only 4.1 inches at Stapleton International Airport…7 inches of new snow fell in Morrison…with 12 inches measured in Castle Rock. North winds gusted to 23 mph at Stapleton International Airport on the 13th.

In 1995…strong winds gusting to nearly 100 mph whipped across the foothills west of Denver. The strongest wind gusts included 98 mph atop squaw mountain and 75 mph at the Eldora Ski Area. West-northwest winds gusted to 41 mph at Denver International Airport on the 13th.


In 1921…downslope Chinook winds produced warm temperatures in the city…which resulted in 4 temperature records. High temperatures of 72 degrees on the 13th and 68 degrees on the 15th were record maximums for the dates. Low temperatures of 47 degrees on both the 12th and 13th were record high minimums for the dates. West winds were sustained to 38 mph on the 12th and to 25 mph on the 13th.

» Click here to read the rest of December 11 to December 17: This Week in Denver Weather History

Join the Discussion - Post your commentJoin the Discussion!

Thornton breaks out of the chill for Friday and the weekend

Friday, December 9th, 2016 5:25am MDT

Following a few days of Arctic cold, we see a return to more seasonal type temperatures and conditions for the three-day period. Overall warmer mercury readings and calmer weather conditions can be expected but a weak disturbance may mix things up just a bit Saturday. All-in-all, it should be a decent weekend for the city’s annual Winterfest.

  • Stay up to date with Thornton’s weather: Be sure to ‘like’ us on Facebook, follow us on Twitter and add us to your Google+ circles.

For Friday we start out quite cold and in the single digits. However we will be warming up nicely with highs right around 40 degrees – as long as the lingering snow cover doesn’t inhibit temperatures too much. Look for mostly sunny skies above throughout the day. Tonight we’ll be dipping down with lows in the low 20s.

On Saturday we will see mostly to partly sunny skies for most of the day with some increase in cloud cover in the afternoon and evening as a disturbance pushes through. Look for high temperatures in the upper 40s. As that system moves in, we stand just a slight chance to see a sprinkle of rain in the afternoon then a few snowflakes overnight and into Sunday morning. Lows Saturday night will be down to the mid to upper 20s.

Sunday starts out with the potential for a few lingering flurries and mostly cloudy skies. However as we get later into the morning cloud cover will decrease leaving partly to mostly sunny skies for the rest of the day. Temperatures will be topping out right near the average of 43 degrees.

Looking into next week, Monday should be somewhat similar to this weekend with dry conditions and temperatures close to normal. After that, we are watching another blast of cold air set to impact us starting Tuesday. Right now it doesn’t look like the cold with it will be extreme as the last blast but it will have a definite impact toward the colder side of things.

Have a great weekend!

Join the Discussion - Post your commentJoin the Discussion!

John Glenn, First US Astronaut to Orbit the Earth, Dies at 95

Friday, December 9th, 2016 4:17am MDT

John Glenn, the first U.S. astronaut to orbit the earth, has died at age 95, officials said. Glenn passed away Thursday, more than a week after being admitted to the Ohio State University’s James Cancer Hospital. The John Glenn College of Public Affairs at OSU made the announcement. U.S. President Barack Obama issued a statement saying… » Click here to read the rest of John Glenn, First US Astronaut to Orbit the Earth, Dies at 95

Join the Discussion - Post your commentJoin the Discussion!

The sun and dry conditions return but the Arctic cold remains

Thursday, December 8th, 2016 5:13am MDT

Our latest storm system has moved out and as long as you are looking out a window from the inside, today won’t seem too bad. Step outside though and you will be hit with the realization that we are seeing some extremely cold temperatures.

We start out the day with mercury readings well below zero, the first time we have gone negative since January 5, 2015. This type of cold is certainly not unusual but it doesn’t make it any more tolerable. Early on there will be some fog in low-lying areas, particularly along the Platte, so be careful. After that we’ll see mostly sunny skies throughout.

Despite the sun, temperatures are going to struggle to recover and we expect to see a high only in the mid to upper teens. Bundle up if you head out! How cold is it right now? Check our live gauges.

Join the Discussion - Post your commentJoin the Discussion!

Wednesday to see snow ending, cold to remain in place

Wednesday, December 7th, 2016 5:35am MDT

Unfortunately we didn’t end up with the snow accumulations we had hoped for as drier air kept things from materializing quite as expected. While the snow will be coming to an end, the cold will linger and make things uncomfortable outside.

We start out under cloudy skies and light snow. Look for the white stuff to taper off with only a few flurries by mid-morning then ending entirely by noon. Only light additional accumulations are expected. By the end of the day we should start to see the sun make an appearance.

In terms of temperatures, readings are going to stay relatively constant today and quite cold. Look for a high in the teens.

Tonight, with clearing skies, the mercury is going to plunge to below zero. Assuming it does, this will be our first time in sub-zero territory in 23 months.

Please allow extra time this morning for your commute and stay warm.

Keep an eye on the temperature here.

Join the Discussion - Post your commentJoin the Discussion!

November 2016 weather recap: Month was much warmer than normal, offered little precip

Tuesday, December 6th, 2016 2:18pm MDT

The month of November 2016 was certainly an unusual one for Thornton.  Despite a turn toward colder weather at the end, the extraordinary warmth at the start was the dominating feature. We did finally receive our first snow of the season although we are far behind normal for the season.

Dominating high pressure was a recurring theme for the first half of the month.  This kept storm systems and colder temperatures at bay bringing unseasonably warm mercury readings.  Every one of the first 16 days of the month saw temperatures in excess of 60 degrees, five saw readings warmer than 70 degrees and one even hit over 80 degrees.

A series of troughs and cold fronts finally brought an end to the record-setting warmth.  After recording 81.5 degrees of the 16th, we followed with a 40.9 degree high on the 17th.  The 17th also brought our first, and thus far only, snowfall of the season.  The balance of the month saw things return to a more typical November weather pattern.

Thornton’s average monthly temperature for November 2016 came in at 43.9 degrees.  This was far above Denver’s historical average for the month of 38.3 degrees.  Out at the airport where the Mile High City’s official measurements are kept, the average came in warmer still at 45.1 degrees.  That put November 2016 into the books at the 10th warmest November in Denver weather history.

Temperatures in Thornton ranged from the aforementioned high of 81.5 degrees on the 16th down to a low of 13 degrees on the morning of the 30th.  DIA’s high was 80 degrees and its low 10 degrees, each on the same day as Thornton’s maximum and minimum.  The 80 degree reading on the 16th was not only a record for the date but also the latest 80 degree temperature ever recorded in Denver.

In terms of precipitation, Denver averages 0.61 inches during the month of November.  Thornton fell far short of that with a mere 0.24 inches of precip in the bucket. Out at the airport, Denver fared better with 0.52 inches.

Thornton recorded 2.2 inches of snow for the month while Denver ended with 1.7 inches.  Both were far below the November average of 8.7 inches and comprise the only snowfall we have seen this season.  The snow on the 17th was the third latest first seasonal snowfall on record in Denver.

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

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

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

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

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

From the National Weather Service:

638 AM MST THU DEC 1 2016




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              80   11/16/2016
 LOW              -18   11/29/1877
HIGHEST            80R  11/16        73       7       75  11/03
LOWEST             10   11/30         6       4        3  11/27
AVG. MAXIMUM     59.9              52.1     7.8     51.2
AVG. MINIMUM     30.4              24.5     5.9     25.7
MEAN             45.1              38.3     6.8     38.5
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      1               2.3    -1.3        5
DAYS MIN <= 32     15              23.4    -8.4       24
DAYS MIN <= 0 0 0.6 -0.6 0 PRECIPITATION (INCHES) RECORD MAXIMUM 3.21 1946 MINIMUM T 1899 1901 1949 TOTALS 0.52 0.61 -0.09 2.13 DAILY AVG. 0.02 0.02 0.00 0.07 DAYS >= .01         2               4.7    -2.7       11
DAYS >= .10         2               1.6     0.4        6
DAYS >= .50         0               0.0     0.0        1
DAYS >= 1.00        0               0.0     0.0        0
 24 HR. TOTAL    0.30   11/22 TO 11/22           11/04 TO 11/05

 TOTAL            1.7               8.7
RECORD NOVEMBER  42.5                      1946

HEATING TOTAL     586               801    -215      789
 SINCE 7/1        896              1382    -486     1090
COOLING TOTAL       0                 0       0        0
 SINCE 1/1        878               769     109      877

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

AVERAGE WIND SPEED              9.8

AVERAGE SKY COVER           0.40
NUMBER OF DAYS FAIR           14
NUMBER OF DAYS PC             12


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

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s December preview: With arrival of winter, cold and snow increase

Tuesday, December 6th, 2016 11:32am MDT

The month of December brings with it the official start of winter and oftentimes, colder and snowier weather conditions. It however can also offer unseasonably warm temperatures and bone dry conditions.  Given our recent mild and dry weather, we are certainly hoping for a change in the coming month.

Overall December’s monthly mean temperature of 30.0 degrees (1981 – 2010 averages) makes it our coldest month.  Snow is always on everyone’s mind this time of year but December is only our 3rd snowiest month behind March and November with an average of 8.5 inches of the white stuff.

We closed out November quite wet and chilly and that is expected to continue into the first part of December.  Long term models then point to a continuation of above normal precipitation but near normal temperatures.

Get all the details on Thornton’s December weather including a look back at historical events and a look at the long range forecast in our December weather preview here.

  • Stay up to date with Thornton’s weather: Be sure to ‘like’ us on Facebook, follow us on Twitter and add us to your Google+ circles.
Join the Discussion - Post your commentJoin the Discussion!

Wintry blast set to impact Thornton with bitter cold and snow

Tuesday, December 6th, 2016 5:17am MDT

The much-anticipated (perhaps dreaded) storm is working its way toward us and while delayed a bit, is still expected to have the impact on our weather we have been talking about. We will see a significant change in temperatures as well as our second snowfall of the season.

We start out the day with some sun but clouds will gradually be increasing as the day progresses. Temperatures today will top out close to the freezing mark, likely a couple of degrees below.

The afternoon may bring some flurries but right now it looks like snow won’t start spreading until after 6:00pm. From there it is expected to last into tomorrow morning. The later arrival may spare this evening’s commute much heartache but tomorrow morning’s could be a rough one. Overnight tonight temperatures will dip into the single digits.

A Winter Weather Advisory is in effect from 6:00pm this evening until noon Wednesday. That means that travel could become difficult with slick roads and limited visibilities. Please be careful.

For all the latest, head over to our Winter Weather Briefing Page.

Join the Discussion - Post your commentJoin the Discussion!

Thornton to start out the workweek warm but big changes arrive soon

Monday, December 5th, 2016 5:17am MDT

We will enjoy one more mild day Monday, albeit with some wind, then the weather will change considerably. The mid-week is going to feature bone-chilling cold and even a shot of snow.

For today look for mostly to partly sunny skies to be above throughout. Warming, downslope winds will be breezy at times, particularly from late morning into the evening.

Temperatures today will climb to highs in the low 50s. Overnight tonight we will begin to feel the effects of the approaching system as temperatures drop to the teens.

We will then see three days straight with mercury readings failing to climb above freezing and in fact will be well below Wednesday and Thursday.

In terms of snow, we may see a flurry overnight tonight but with little or no accumulation. The best chances will come tomorrow afternoon into Wednesday morning. How much? It is still a bit early and models are not in agreement but we do see the potential for 3 to 6 inches for the entire event.

We’ll get a better feel for it over the next 24 hours. In the meantime, enjoy today’s relative warmth and use our Winter Weather Briefing Page as your one-stop-shop for the coming storm.

Join the Discussion - Post your commentJoin the Discussion!