Thornton, Colorado, USA
UpdatedWed, 16-Jan-2019 9:25pm MST 


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

Our first freeze and snow could come at any time

Thursday, October 4th, 2018 5:56pm MST

While we enjoyed a nice day today with temperatures a good bit above normal, it might be time to start thinking about snow and cold. While we don’t have any freezing temps or any of the white stuff in the immediate forecast, history shows us it could happen any time now. You may start thinking about getting those sprinklers blown out, swamp coolers put away and other winterization tasks done.

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s October weather preview: Fall arrives, usually with the first freeze and snow

Thursday, October 4th, 2018 5:00pm MST

Thornton, Colorado October weather preview.With the first full month of fall here, October usually brings one of the quietest weather months in the Denver area with plenty of mild, sunny days and clear, cool nights.

October is historically the second sunniest month and conditions are generally calm.

However we also will usually see our first taste of winter during the month with the first freeze and first snowfall of the season.

Temperatures as well will start to drop and by the end of the month the average nighttime lows are below freezing.

For complete details on our historical October weather and what we can expect in the coming month, read our complete October weather preview here.

  • Don’t miss a thing when it comes to our ever-changing 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!

September 2018 weather recap: Warmer than normal but near average precipitation

Thursday, October 4th, 2018 4:50pm MST

High pressure was a recurring theme for the month of September in 2018.  This was the driving force behind many days with above normal temperatures and a mere three days with precipitation.

The ridge seemed to show little movement in the month keeping moisture at bay and any cooler air to the north. The middle of the month in particular bore the brunt of this feature when we saw a string of nine days of 90 degree or higher readings.

Thornton’s average temperature for the month came in at 64.8 degrees.  Denver’s long term average for the month is 63.4 degrees so we were a good bit above that.

Out at DIA where the Mile High City’s official measurements are kept, it was considerably warmer with an average this year 67.8 degrees. That puts the month in the books as the sixth warmest September on record – with the asterisk that should always comes with Denver’s stats since the station moved to the airport.

Thornton saw its warmest temperature of 94.4 degrees on the 16th of the month and its coldest of 35.3 degrees on the 29th.  Denver saw its maximum for the month of 96 degrees on the 13th and its coldest reading of 36 degrees on the 29th.

Officially, Denver saw four records tied or broken.  On the 10th the record high of 93 degrees was tied, a 93 degree reading on the 11th broke the record high for the date and a high of 94 degrees on the 14th was tied the record high. Lastly, a record high minimum of 64 degrees was set on the morning of the 13th.

In terms of precipitation, Denver averages 0.96 inches during September.  In Thornton, we saw 1.02 inches fall in the bucket with virtually all of that coming on two days. Denver was much drier with only 0.18 inches.

Click here to view Thornton’s September 2018 climate report.

Thornton, Colorado's September 2018 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s September 2018 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's September 2018 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s September 2018 precipitation summary. (ThorntonWeather.com)

303 PM MDT MON OCT 1 2018




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              97   09/03/2017
 LOW               17   09/29/1985
HIGHEST            96   09/13        91       5       97  09/03
LOWEST             36   09/29        35       1       40  09/20
AVG. MAXIMUM     82.7              78.5     4.2     79.0
AVG. MINIMUM     52.8              48.3     4.5     51.3
MEAN             67.8              63.4     4.4     65.1
DAYS MAX >= 90      9               3.4     5.6        9
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               0.8    -0.8        0
DAYS MIN <= 0 0 0.0 0.0 0 PRECIPITATION (INCHES) RECORD MAXIMUM 5.61 2013 MINIMUM T 1892 1944 TOTALS 0.18 0.96 -0.78 1.26 DAILY AVG. 0.01 0.03 -0.02 0.04 DAYS >= .01         5               6.5    -1.5        6
DAYS >= .10         0               3.3    -3.3        2
DAYS >= .50         0               0.6    -0.6        1
DAYS >= 1.00        0               0.1    -0.1        0
 24 HR. TOTAL    0.08   09/19

 TOTAL            0.0
 TOTAL           17.2  1971         1.3

HEATING TOTAL      69               125     -56      122
 SINCE 7/1         78               141     -63      130
COOLING TOTAL     160                76      84      131
 SINCE 1/1       1022               764     258      880

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

AVERAGE WIND SPEED              9.7

AVERAGE SKY COVER           0.40
NUMBER OF DAYS FAIR           13
NUMBER OF DAYS PC             13


THUNDERSTORMS             5   MIXED PRECIP           0
HEAVY RAIN                0   MODERATE RAIN          0
LIGHT RAIN                9   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   0
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   3
FOG                       5   HAZE                   2

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s Thursday to offer cool temps, slight chance for showers

Thursday, October 4th, 2018 5:28am MST

Following the cold front that moved through yesterday evening, our day starts out a bit unsettled. By this afternoon though, skies will be clearing, albeit with a lingering chance for a shower.

Cloudy skies start off the day then by mid-morning we will begin to clear with mostly sunny skies arriving for the afternoon and evening. A few drops of rain might fall this morning with a bit better chance of an isolated shower in the afternoon. Temperatures cool a good bit today with highs expected to top out in the mid-60s.

Tonight, skies will continue to clear with lows in the mid-40s.

Keep an eye out for any showers here.

Join the Discussion - Post your commentJoin the Discussion!

Unseasonably warm temps for Wednesday; cooler, wetter weather arrive tonight

Wednesday, October 3rd, 2018 5:03am MST

Thornton will get a mild day today with a slight chance for a PM storm. Tonight though, a system moves through with decent chances for rain and signifies a change in the overall patter which will see us cool down a good bit for the foreseeable future.

For today, mostly sunny skies will be above for much of the day with cloud cover increasing in the mid to late afternoon through tonight. Winds will initially be calm then become breezy by late morning and lasting into the evening as the system moves in. Temperatures will top out near the 80 degree mark, well above the average high of 71 degrees for the date.

Late afternoon may see a shower / thunderstorm pop up with chances for showers increasing as we get closer to sunset and then lasting through much of the night. There is not, however, a lot of moisture with the system so while we do believe we will see some rain, it isn’t expected to amount to a whole lot.

Looking ahead, Thursday and Friday will cool to levels a bit below normal. After that, we see even cooler temperatures with better chances for precipitation. By early next week, we could be looking at our first snow of the season although right now, it looks like if it happens, it wouldn’t be much. Keep an eye on our extended weather forecast for more.

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s Tuesday should finally warm up, remains mostly cloudy though

Tuesday, October 2nd, 2018 5:04am MST

Well, let’s try again at forecasting some warmer temperatures. 😉 We do believe we will bust out of the cool from the last couple of days and see readings a bit above normal today but with a good bit of cloud cover and a slight chance for storms.

The day starts off with mostly cloudy skies and we expect to see a good bit of cover throughout the day. Temperatures should warm to the mid-70s, maybe a bit above, as it appears the cloud cover shouldn’t have too much of an impact. Mid to late afternoon brings just a slight chance for storms on the Front Range although right now it isn’t very likely.

Tonight, skies will begin to clear some with lows in the mid-50s.

Join the Discussion - Post your commentJoin the Discussion!

First day of October to offer seasonal temps, a good bit of cloud cover

Monday, October 1st, 2018 5:00am MST

With a good bit of moisture aloft, we will see a good bit of cloud cover but unfortunately only the slightest chance for precipitation. Temperatures do warm up today though to right near normal.

The day starts out with a few spots of fog and then we will see mostly cloudy skies above for the balance of the day. Mid to late afternoon may bring a shower or thunderstorm but right now the chances look slim.

As for temperatures, the average high for today’s date is 72 degrees and we should top out right near that.

Tonight, skies remain mostly cloudy with lows in the low 50s.

Join the Discussion - Post your commentJoin the Discussion!

September 30 to October 6: This week in Denver weather history

Monday, October 1st, 2018 2:28am MST
This week in Denver weather history

September 30 to October 6: This week in Denver weather history

Our look back at this week in Denver weather history shows what has historically been a relatively quiet week. However that isn’t to say there aren’t events of note including days with severe thunderstorms, including one date that brought multiple tornadoes.

Be sure to scroll down to the bottom to check out video of one of the tornadoes that struck near Brighton on October 4, 2004.

From the National Weather Service:


In 1898…south winds were sustained to 41 mph with gusts to 54 mph.

In 1940…a late season thunderstorm in the city caused one lightning death.

In 1944…the month ended with a trace of rain on this date and for the month. A trace of rain also occurred on the 4th…9th…and 10th. There was no measurable precipitation for the month. The total of a trace of precipitation for the month equaled the driest September on record first set in 1892.

In 2009…a trained spotter in Coal Creek Canyon…recorded a peak wind gust to 88 mph.


In 1959…heavy snowfall totaled 5.9 inches at Stapleton Airport. Winds were light.


In 1892…the highest temperature ever recorded in October… 90 degrees…occurred. This is also the latest 90 degree reading of the season.

In 1898…southwest winds were sustained to 40 mph with gusts to 49 mph in the city.

In 1927…a trace of snow was the only snow of the month… Ranking the year…amongst several other years…the second least snowiest on record.

In 1971…a wind gust to 90 mph was recorded at Buckley Field in Aurora. The severe winds caused damage in northeast metro Denver. A brick wall of a bowling alley was blown down…the roof was blown off a garage…and some business signs were damaged. A man in the bowling alley was injured by flying glass. Northwest winds gusted to 43 mph at Stapleton International Airport.

In 1994…unusually strong thunderstorms for so late in the season pummeled metro Denver with large hail. The largest hail…2 inches in diameter…fell at Buckley Field. Hail 1 3/4 inches in diameter fell 7 miles northeast of Boulder and at Niwot. Hail 3/4 to 1 1/2 inches in diameter fell in Boulder…Arvada…wheat Ridge…Edgewater…capitol hill and northwest Denver…Bennett…and Strasburg. Hail of unknown size damaged a Boeing 737 aircraft and injured both pilots at Stapleton International Airport when the windshield was broken out on takeoff. Half inch diameter hail fell at Stapleton International Airport where northwest winds gusted to 40 mph and rainfall totaled 0.82 inch.

In 2009…strong downslope winds near the foothills produced a peak wind gust to 84 mph at the national wind technology center near Rocky Flats.

In 2014…severe thunderstorms produced wind gusts to 60 mph across parts of Arapahoe and Denver Counties. The intense wind gusts downed trees and power lines which caused a power outage near the Denver Technology Center. At Denver International Airport…a peak wind gust to 37 mph was measured from the northwest.


In 1903…southwest winds were sustained to 42 mph with gusts as high as 60 mph. The strong Chinook winds warmed the temperature to a high of 78 degrees.

In 1910…an apparent dry microburst produced sustained northeast winds to 43 mph.

In 1934…a trace of rain was the only precipitation of the month. This was the driest October on record.


In 1875…very dense haze hid the mountains from view as observed from the city.

In 1933…rainfall of just 0.01 inch was the only precipitation of the month. This was the second driest October on record.

In 1954…the low temperature cooled to only 60 degrees…the all-time record high minimum for the month October.


In 1969…the first snowfall of the season totaled 16.0 inches at Stapleton International Airport. There was a thunder snow shower on the evening of the 3rd…but otherwise little wind with the storm. The greatest snow depth on the ground was 8 inches due to melting. Heavy wet snow accumulated on trees…which were still in full leaf…and caused widespread damage from broken limbs and downed utility lines.

» Click here to read the rest of September 30 to October 6: This week in Denver weather history

Join the Discussion - Post your commentJoin the Discussion!

September 2018 top shots: Monthly photo slideshow

Sunday, September 30th, 2018 6:15pm MST
Dramatic skies over Adams County start out the month of September. (Jessica Fey)

Dramatic skies over Adams County start out the month of September. (Jessica Fey)

The month of September is typically one of the more pleasant months in Colorado.  Temperatures are usually comfortable and there is not normally a lot of weather drama.  That however does not mean there aren’t plenty of photo opportunities.

Wildlife is still quite active along the Front Range and flowers will hold on to their petals for at least the first part of the month.  Then of course there is the weather which you never know what to expect.  Thunderstorms, heavy rain, and even snow are a possibility.

  • Slideshow updated September 30, 2018
  • To learn more about how to send your photo to us for inclusion in the slideshow, see below the slideshow.

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

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

What is missing in the slideshow above?  Your photo!

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

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

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

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

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

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

So come on, get those camera’s rolling!

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s three-day period starts much cooler, will warm right back up

Friday, September 28th, 2018 5:09am MST

A cold front arriving this morning is going to send the mercury down quite a ways below normal. However, we will quickly rebound with above normal temps Saturday and Sunday.

For today, the front is going to bring with it cloud cover this morning then this afternoon skies will begin to clear. Temperatures will be cool with highs only in the mid to upper 50s. Tonight, look for partly cloudy skies and lows in the low 40s.

Saturday bounces right back with highs jumping to the mid-80s. Mostly sunny skies will be above. Overnight Saturday night into Sunday morning, mostly clear skies will be above with lows in the mid-40s.

We close out the weekend with a dip in temperatures but remain quite nice. Look for mostly sunny skies Sunday with highs in the mid-70s.

Have a fantastic weekend!

Join the Discussion - Post your commentJoin the Discussion!