Thornton, Colorado, USA
UpdatedThu, 23-Nov-2017 3:15pm 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

More than 120,000 flee rumbling Bali volcano

Thursday, September 28th, 2017 5:43pm MST

More than 122,000 people have fled their homes on the resort island of Bali, fearful that a rumbling volcano could erupt at any time, disaster officials said. Mount Agung, 75 kilometres (47 miles) from the resort hub of Kuta, has been shaking since August and threatening to erupt for the first time since 1963 — a… » Click here to read the rest of More than 120,000 flee rumbling Bali volcano

Join the Discussion - Post your commentJoin the Discussion!

September 24 to September 30: This week in Denver weather history

Thursday, September 28th, 2017 9:14am MST
This Week In Denver Weather History

September 24 to September 30: This week in Denver weather history

Colorado’s famously inconsistent weather can be seen in our look back at this week in Denver weather history. Not only do we see damaging thunderstorms and winds but even major snowstorms that deposited more than a foot of the white stuff on the city.

From the National Weather Service:


In 2000…the first snowstorm of the season brought heavy snow to areas in and near the foothills. While the heaviest snow fell north of metro Denver…6 inches were measured in Boulder…4 inches at both Castle Rock and Morrison…but only 0.2 inch at the site of the former Stapleton International Airport where most of the precipitation fell as rain. At Denver International Airport where drizzle and rain fell on the 23rd… Snowfall during the early morning of the 24th was estimated at 2.1 inches due to melting. The foothills west of Denver received more snow with 10 inches measured at conifer…9 inches 11 miles southwest of Morrison… 8 inches atop Crow Hill…7 inches at Chief Hosa…and 5 inches at Ralston Reservoir.


In 1901…northwest winds were sustained to 50 mph with gusts as high as 57 mph in the city.

In 1932…thunderstorm rainfall of only 0.11 inch was the only measurable precipitation for the month that year in the city.

In 1986…a very strong wind storm roared across metro Denver. Boulder was hit hardest. Winds peaked to 131 mph at the National Center for Atmospheric Research. This is thought to be the highest wind gust ever recorded in Boulder during September. A wind gust to 118 mph was clocked on Davidson Mesa and to 92 mph near Niwot. Gusts of 70 to 80 mph were common over all of Boulder where an estimated 70 to 90 large trees were uprooted. About a dozen of them hit cars. Two walls of a building under construction were toppled and solar panels were blown off a house. Traffic lights and power lines were downed. Damage to power equipment alone was estimated at 100 thousand dollars. Wind gusts to 87 mph at Jefferson County Airport damaged two planes. A woman was seriously injured in Boulder. She suffered a fractured skull when struck by a falling tree limb. Trees were also downed in Louisville and Lafayette. West wind gusts to 45 mph were recorded at Stapleton International Airport.


In 1873…a fire was sighted in the woods near Platte Canyon… Probably caused by high winds blowing sparks among the timber.

In 1896…an apparent cold front produced northeast sustained winds to 40 mph with gusts to 48 mph.

In 1910…a thunderstorm produced sustained north winds to 51 mph. This was the highest recorded wind speed in the city in September at the time.

In 1936…a vigorous cold front produced a deadly dust storm in the city. North winds sustained to 36 mph with gusts to 38 mph produced much blowing dense dust…greatly restricting the visibility. The temperature plunged from a high of 84 degrees to a low of 38 degrees by midnight. The weather observer described the event with the following. “at 6:00 pm the temperature was 82 degrees and the wind velocity was only 4 mph; but with the wind shifting to the north and the barometer rising quite rapidly…the temperature fell sharply. By 6:30 pm…the wind velocity increased rapidly and by 7:00 pm had reached a maximum sustained velocity of 36 mph…bringing with it clouds of dust which had been picked up by gale force winds in southern Wyoming and northern Colorado…covering the city. The visibility was generally reduced to about 1/4 mile; however…the whirling of the dust down the streets and alleys…the visibility was at times somewhat less. Airplanes were grounded…traffic was halted at times…and homes filled with dust. The strong winds damaged electric power and telephone lines…leaving homes in darkness for a few hours in the city and for 18 hours in suburban towns and putting 2500 telephones out of service because of broken lines. An electric lineman was killed while repairing damage by the high winds. The dust storm was followed by rain that began falling at 10:55 pm…which turned to snow during the early morning hours of the 26th. A major snow storm followed on the 27th through the 29th.”

In 1999…high winds developed in the foothills of Boulder County. Winds gusted to 90 mph at Wondervu.


In 1908…apparent post-frontal rain changed to snow overnight and totaled 6.5 inches in downtown Denver. This was the first snow of the season. Precipitation totaled 0.76 inch. North winds were sustained to 39 mph on the 25th.


In 1996…an early season snowstorm brought heavy snow to the Front Range eastern foothills. Snowfall totals included: 8 to 12 inches around conifer…7 inches on Floyd Hill…and 6 inches at both Bailey and Chief Hosa. Snowfall totaled only 4.7 inches at the site of the former Stapleton International Airport. This was the first measurable snow of the season. After the passage of a strong cold front…north winds gusted to 38 mph at Denver International Airport on the 25th.

» Click here to read the rest of September 24 to September 30: This week in Denver weather history

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s Thursday starts wet, showers then to ease, temps remain cool

Thursday, September 28th, 2017 5:03am MST

A very wet morning out there as rain has been falling since midnight. We will see that start to come to an end this morning but it will remain cloudy and cool.

Cloudy skies start off the day and are expected to remain with us throughout the daytime hours. The rain will continue through mid-morning or so then begin to ease this morning as shower activity shifts to the northeast. Temperatures will again be much cooler than normal with highs in the mid to upper 50s.

Tonight there may be a few drops of rain but otherwise we will see some clearing begin. Lows tonight will be in the mid-40s.

Keep an eye on the showers here.

Join the Discussion - Post your commentJoin the Discussion!

Next storm system to bring damp, cool weather conditions Wednesday

Wednesday, September 27th, 2017 5:07am MST

Hopefully you enjoyed the brief bit of sun and somewhat warmer temperatures yesterday because today we transition back to conditions like we saw this past weekend. A storm system preparing to enter the state will bring us some shower activity and cooler temps for the next 48 hours or so.

Mostly cloudy skies can be expected above today with little break in the cloud coverage. Temperatures will top out in the upper 50s, again well below the average for the date of 74 degrees. Some light sprinkles of rain will be possible this morning into the early afternoon.

The evening and overnight hours bring better chances for appreciable precipitation. Lows tonight will be in the mid-40s.

Keep an eye out for the showers with our radar here.

Join the Discussion - Post your commentJoin the Discussion!

Trump to visit Puerto Rico amid criticism of storm response

Wednesday, September 27th, 2017 4:14am MST

US President Donald Trump, under fire for his response to the storms that ravaged Puerto Rico, announced Tuesday that he will visit the hurricane-battered island next week. “I’m going to Puerto Rico on Tuesday,” Trump told reporters at the White House, signalling that October 3 was the first date he could go without interfering with recovery… » Click here to read the rest of Trump to visit Puerto Rico amid criticism of storm response

Join the Discussion - Post your commentJoin the Discussion!

Indonesia ready to divert tourists as Bali volcano rumbles

Tuesday, September 26th, 2017 5:08pm MST

Indonesian authorities are on standby to divert flights destined for the holiday island of Bali as increasingly frequent tremors from a rumbling volcano stoke fears an eruption could be imminent. Mount Agung, about 75 kilometres (47 miles) from the tourist hub of Kuta, has been shaking since August, threatening to erupt for the first time in… » Click here to read the rest of Indonesia ready to divert tourists as Bali volcano rumbles

Join the Discussion - Post your commentJoin the Discussion!

Warmer temperatures, drier conditions for Tuesday

Tuesday, September 26th, 2017 5:35am MST

A bit of a break from the damp conditions of recent days as we should remain dry today. Temperatures though, while warmer, will remain well below normal.

The day starts with mostly cloudy skies then the cover should gradually ease leading to partly sunny skies in the latter half of the day. Conditions will be dry, winds light. In terms of temperatures, look for our highs today to top out in the low to mid-60s. Average for the date is 74 degrees.

Tonight we will still see a good bit of cloud cover and lows will be in the mid-40s.

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s Monday brings more of the same cool, damp weather conditions

Monday, September 25th, 2017 5:09am MST

A virtual repeat of this past weekend’s weather for today with well below normal temperatures and periods of showers. We may see just a bit of sun by the end of the day though signifying a brief period of drying out.

The day starts with cloudy skies and clouds will dominate most of the day. The afternoon and evening may bring just a little bit of easing in the coverage though. Light showers will be possible throughout the day but not we aren’t expecting any notable amounts of precipitation totals. Temperatures will remain well be about 20 degrees below the average for the date of 75 degrees.

Overnight today skies will clear some and we will begin to dry out. It will get quite chilly with lows into tomorrow morning dipping to around 40 degrees.

Some drying out and warming up will occur tomorrow and Wednesday but right now it looks like it won’t be till the weekend when we see the mercury return to near normal. Details in our extended forecast here.

Join the Discussion - Post your commentJoin the Discussion!

Fall Colors 2017: Picks for the top Colorado Front Range spots for leaf peeping

Friday, September 22nd, 2017 8:22am MST
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. Be forewarned though that the western half of the pass is unpaved and twisty.  Editor’s note: The west side of Cottonwood Pass is closed until Summer 2018 so that it can be paved.

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:

Join the Discussion - Post your commentJoin the Discussion!

Following a warm Friday, Thornton’s weekend to cool down considerably

Friday, September 22nd, 2017 5:14am MST

Big changes on the way with our weather. We set a record high temp yesterday, today will be much warmer than normal but after that the mercury will cool considerably Saturday and Sunday and we see good chances for precipitation.

For today, mostly sunny skies start things off then this afternoon as a cold front moves in cloud cover will increase. Winds will be calm this morning but that front will also bring gusty winds in the afternoon and early evening. Temperatures will warm to a high in the low to mid-80s.

This evening brings just a slight chance for some showers. Tonight, mostly cloudy skies will be above with a few sprinkles of rain possible. Overnight lows into Saturday morning will dip to around 50 degrees.

Saturday will see mercury readings about 20 degrees cooler than today as the cold front and a trough make themselves felt. Mostly cloudy skies will be above and some periods of rain will be possible, particularly in the afternoon and evening. Highs tomorrow will top out in the mid-60s.

Overnight Saturday into Sunday, some rain will be possible with cloudy skies above. Lows will be in the mid-40s.

The weekend closes out on Sunday with our coolest day of the period. Highs will only be in the mid to upper 50s. Cloudy skies will be above and some light rain showers will be possible throughout the day with the best chances coming in the afternoon.

Looking ahead into next week, cooler than normal temperatures will be sticking around, at least through the first half of the week.

Join the Discussion - Post your commentJoin the Discussion!