Thornton, Colorado, USA
UpdatedMon, 28-Sep-2020 1:40am MDT 


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September 2020 top shots: Monthly photo slideshow

Sunday, September 27th, 2020 4:23pm MDT
Smoke from the Cameron Peak Fire makes for a beautiful sunset. (John Stavola)

Smoke from the Cameron Peak Fire makes for a beautiful sunset. (John Stavola)

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 27, 2020
  • 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!

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Fall colors 2020: When and where to go for leaf peeping

Friday, September 25th, 2020 7:34am MDT
Rocky Mountain National Park is a prime spot for viewing the fall foliage. (Tony's Takes)

Rocky Mountain National Park is a prime spot for viewing the fall foliage. (Tony’s Takes)

This time of year many folks start thinking about heading to the hills west of Denver in search of gold – fall foliage gold.

Where to go?  Below are five of ThorntonWeather.com’s favorite ones near Denver – plus a few further out and some bonus ideas.  After that, we will tell you where you can find a great website that provides regular updates on viewing conditions.

I-70 Corridor – If you’re looking for the easiest route, then this one is for you.  Simply head west on I-70 about 110 miles to Avon.  Between Vail and Avon, both sides of I-70 are lined beautifully with aspen.

Rocky Mountain National Park – One of the most popular summer destinations in the state is of course also a prime spot to view aspen in all their glory.  Once in the park head toward Bear Lake.  Glacier Gorge Junction provides a beautiful spot and you of course also get to enjoy all the splendor that Rocky Mountain National Park has to offer.  Extend your viewing by taking Trail Ridge Road all the way through to the west side of the park and the Grand Lake and Granby area.

Peak to Peak Highway – This little road trip can be a dual purpose trip – gambling and fall foliage viewing!  Take U.S. 6 through Clear Creek Canyon and then 119 through Blackhawk and Central City.  You can of course stop there if your wallet is fat enough and donate some money to the casinos.  From there continue on 119 toward Nederland.  Take highway 72 toward Ward and Allenspark.  There you will find more golden aspen than you can imagine, all with the Continental Divide nearby.

Colorado Fall Foliage - Average Date of Peak Aspen Colors. Click for larger view. (ThorntonWeather.com)

Colorado Fall Foliage – Average Date of Peak Aspen Colors. Click for larger view. (ThorntonWeather.com)

Poudre Valley Canyon –  Heading north on I-25 take Colorado 14 west and into Poudre Canyon and Roosevelt National Forest.  As you continue west you will come very near timberline as you come to Cameron Pass.  Amazing views abound!

Guanella Pass – This is a nice, relatively short drive from Denver.  From C470 take 85 through Bailey and Conifer, a nice drive unto itself.  When you come to the town of Grant, take the Guanella Pass Scenic and Historic Byway north to Georgetown.  The air is pretty thin along the way as you climb in excess of 11,500 views through the Pike and Arapahoe National Forests.

A couple other possibilities further from the Front Range:

Leadville / Aspen – From Denver take I-70 west to Copper Mountain and then Colorado 91 south over Freemont Pass to Leadville. Along the way there are plenty of viewing opportunities and Leadville is a nice little town to make a stop. From here you can take Highway 24 north back through Minturn and Vail. To extend the drive, take Highway 24 south to Colorado 82 and head toward Aspen. You can stop by the Maroon Bells in White River National Forest to view some of the most photographed mountains in Colorado.

Cottonwood Pass – From Denver take Highway 285 to Buena Vista. Head west on Main Street for seven miles then west on County Road 344 / Colorado 82. From there you start the climb up Cottonwood Pass with absolutely stunning views from the top. If you are up for it, you can continue down the west side of the pass into the Taylor Park area.

Honorable mentions worth considering:

  • Boreas Pass between Breckenridge and Como (County Road 10)
  • Kenosha Pass on Highway 285 between Bailey and Fairplay
  • Independence Pass (Colorado 82 between Aspen and Twin Lakes)
  • Colorado 103 from Evergreen to Echo Lake. Throw in a drive up Mount Evans for a bonus.

If you do head out, be sure to send us your pictures for inclusion in our monthly photo slideshows!

For more information:

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Thornton’s weekend starts off very warm, will end considerably cooler

Friday, September 25th, 2020 4:33am MDT

A bit of a mixed bag of temperatures for the three day period. Friday and Saturday are going to see unusually warm readings however, a cold front will cool things down a good bit on Sunday.

For today, sunny to mostly sunny skies will be above with highs again pushing toward the 90 degree mark. Winds will be a bit breezy in the afternoon. Tonight, lows will drop to the mid-50s under partly clear skies.

Saturday sees an increase in cloud cover but at this time it doesn’t appear that will have much of an impact on temps. Look for highs in the upper 80s with some breezy winds. Saturday night into Sunday morning, lows will be near 50 degrees.

A cold front will be pushing through Sunday and that is going to bring a big change in temperatures. Look for highs only in the mid-60s. The day will start sunny and then there will be just a slight chance for a PM shower.

Have a great weekend!

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Thursday to see climbing temperatures, calm, dry conditions

Thursday, September 24th, 2020 4:40am MDT

If you thought we were done with the 90 degree days for the season, you may have been mistaken. Thornton looks to string together three, very warm days that may hit or break the mark.

For today, sunny skies are going to be above throughout the day. At this time, it looks like smoke should stay to our north although we may see it intrude a bit this evening. Conditions will be dry and overall calm with the exception of some breezy, late afternoon winds. Highs today are going to push to near the 90 degree mark.

Tonight, skies will be clear with lows in the mid-50s.

After today, Friday and Saturday again are expected to see highs near 90 degrees before we see things cool down on Sunday. More in the extended forecast here.

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Mild temperatures and dry conditions Wednesday, smoke to return this afternoon

Wednesday, September 23rd, 2020 5:00am MDT

The first full day of autumn is going to continue our summer-like weather. Temperatures will again be well above normal and smoke from the wildfires will return.

The day starts out with mostly sunny skies and that will continue for most of the day with a few more clouds in the late afternoon. The afternoon is also expected to bring in smoke from the Cameron Peak and Mullen fires. High temperatures today will reach to the mid-80s, about 10 degrees above normal.

Tonight, partly cloudy skies will be above with overnight lows in the low to mid-50s.

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Tuesday brings the arrival of fall, continued mild temperatures and just a slight chance for a storm

Tuesday, September 22nd, 2020 4:58am MDT

Today marks the astronomical change of the seasons with fall beginning at 7:30am. While we will see it cool down slightly, temperatures will remain above normal and there is only the slightest chance for a thunderstorm.

Mostly sunny skies start us off then by mid-morning clouds will increase as moisture begins to build aloft. Highs today will top out in the low to mid-80s, slightly cooler than recent days but still well above the average high of 76 degrees for the date.

We see just a slight chance for thunderstorms and showers from about 3:00pm to 9:00pm. At this time, we are not expecting much out of the storms. Some light rain and gusty winds will be about it, if anything.

Tonight, after the storms move out, partly to mostly cloudy skies will be above and overnight lows drop to the mid-50s.

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Monday brings a continuation of the unusually warm, dry conditions

Monday, September 21st, 2020 4:55am MDT

If you were looking for a break from the heat, that isn’t going to happen soon. With a high pressure ridge stubbornly in place, we can expect more of the same warm, dry conditions to last through the workweek.

Today starts off with sunny skies but with some haze from wildfire smoke. The afternoon will bring a few clouds and while some showers are possible in the area, they are expected to remain south of us. High temperatures today will again climb to the mid-80s, about 10 degrees above normal for the date.

Tonight, skies will be partly cloudy with lows in the mid-50s.

Looking ahead, expect continued temperatures well above normal to last until Friday. We do have some hope for cooler weather this weekend.

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September 20 to September 26: This week in Denver weather history

Sunday, September 20th, 2020 4:56am MDT

This Week in Denver Weather History

Looking back at this week in Denver history we start to see more of the signs that summer is coming to an end and fall and winter are right around the corner.  Summer-like severe weather can still occur but we also start to see more cold temperatures and occasions with snow become more prevalent.

From the National Weather Service:


In 1921…an apparent Bora produced northwest winds sustained to 44 mph with gusts to 64 mph.

In 1955…hail stones 1/2 to 3/4 inch in diameter were reported across parts of the city of Denver.

In 1992…weather observers at Buckley Air National Guard base sighted two tornados southeast of the base.  The tornados were short-lived and caused no injuries or damage.


In 1963…heavy rain and hail caused local flooding in southeast Denver.  Thunderstorm rainfall was only 0.60 inch at Stapleton Airport on the 20th.

In 1983…the cold front on the 19th brought an unusually cold air mass into metro Denver for so early in the season.  The temperature dipped to a daily record minimum of 28 degrees on both days.

In 1995…a vigorous late summer storm brought the season’s first heavy snow to portions of metro Denver.  Millions of trees were damaged and power lines downed as 4 to 8 inches of heavy wet snow settled on fully leafed trees in the Boulder and Denver areas.  Branches snapped and trees split under the weight of heavy snow…downing power lines. Firefighters responded to numerous transformer fires. Around 100 thousand people were left without electricity in Boulder and Denver areas alone.  It took over a week to fully restore power to some areas.  Insurance claims were estimated to be around 6 million dollars to homes in metro Denver and about 500 thousand dollars in damage to automobiles.  It was estimated that about 80 percent of 125 million dollars worth of city owned trees in Denver were damaged.  Snowfall totaled 7.4 inches at the site of the former Stapleton International Airport where the greatest depth of snow on the ground was only 4 inches due to melting.  Temperature records were set on the 21st when the thermometer dipped to a record low reading of 27 degrees and climbed to a high of only 36 degrees… Setting a record low maximum for the date.  North winds gusted to 29 mph at Denver International Airport on the 20th.


In 1902…a thunderstorm on the 20th…in advance of an apparent cold front…produced rain…hail…and northwest winds to 40 mph with gusts to 48 mph.  Widespread rain developed behind the cold front and totaled 3.21 inches from the evening of the 20th through the early afternoon of the 22nd.  The 2.70 inches of precipitation recorded from 800 pm on the 20th to 800 pm on the 21st is the greatest 24 hour precipitation ever recorded in the month of September.  The temperature dipped from a high of 80 degrees on the 20th to a high of only 51 degrees on the 21st.


In 1951…4.2 inches of snow fell at Stapleton Airport… Where northeast winds gusted to 27 mph.  This was the first snowfall of the season in Denver…marking the end of the second shortest snow-free period on record…109 days…from June 4th through September 20th.  A trace of snow fell on June 3rd.

In 1984…thunderstorm winds gusted to 56 mph at Stapleton Airport.

In 1992…the only precipitation of the month at Stapleton International Airport…0.01 inch of rain…fell from a brief shower around daybreak.
21-22 in 1870…strong winds occurred in the foothills and in Boulder and Denver.

In 1895…rain changed to snow overnight and totaled 11.4 inches in downtown Denver.  This was the first snowfall of the season and the second heaviest first snowfall of the season on record.  North winds were sustained to 27 mph with gusts to 30 mph on the 21st.

In 2009…an early season storm brought moderate to heavy snow to the foothills of clear creek…Jefferson and Park counties…west and southwest of Denver. A trained spotter…4 miles west-northwest of Conifer… Was the big winner with 14 inches of snow. Storm totals elsewhere generally ranged from 5 to 10 inches.


In 1913…a thunderstorm produced northwest winds sustained to 40 mph with gusts to 44 mph.

In 1946…a trace of snow fell in downtown Denver.  This marked the start of the longest snow season on record… 263 days through June 11…1947…when a trace of snow also fell.

» Click here to read the rest of September 20 to September 26: This week in Denver weather history

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Thornton’s weekend to continue with the warm weather, conditions remain dry

Friday, September 18th, 2020 6:05am MDT

Not really any change in our weather for the three day period. Temperatures will continue to be well above normal and while we will have some clouds, no precipitation is expected.

For Friday, we start out sunny then as moisture aloft increases, some clouds will build in the afternoon. Once again, we can expect to have smoke from regional wildfires. Highs will be in the mid to upper 80s. Tonight, partly cloudy skies will be above with lows in the mid-50s.

Saturday will be the warmest day of the weekend with highs pushing close to 90 degrees under mostly sunny skies. Conditions will be calm and dry. Saturday night, partly cloudy skies will be above with lows in the low to mid-50s.

We close out the weekend on Sunday with a pleasant day. Look for highs in the mid-80s under mostly sunny skies.

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Thursday’s weather to bring very warm temps, a bit less smoke

Thursday, September 17th, 2020 5:06am MDT

Another day of mild temperatures and dry, calm conditions. We will see warmer temperatures today and, with any luck, less smoke above.

Sunny skies with smoke / haze start us off this morning. This afternoon should see smoke decrease and maybe just a cloud or two appear. High temperatures today will be climbing to the mid-80s.

Tonight, skies remain clear with overnight lows in the low 50s.

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