Thornton, Colorado, USA
UpdatedSat, 23-Sep-2017 3:15am 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

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

Friday, September 22nd, 2017 8:22am 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. 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 MDT

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!

Record high temperature set for September 21

Thursday, September 21st, 2017 5:17pm MDT

Record High TemperaturesIn our morning forecast we said it was possible we would break the record high temperature and indeed we did. In fact, we smashed it.

At 3:05pm the mercury at Denver International Airport where the Mile High City’s official records are kept topped out at 92 degrees.  This easily bested the previous record high for this date of 89 degrees set in 2015.

Here in Thornton we were just a touch cooler with our high hitting 91 degrees at 3:19pm.

Change is coming soon though with high temperatures this weekend being much cooler.  A trough and associated cold front will be moving through and that will translate to Saturday highs in the mid to upper 60s and only the upper 50s on Sunday.

Details in our extended forecast here.

Join the Discussion - Post your commentJoin the Discussion!

Thursday offers lots of sun, very mild temps, a bit of wind

Thursday, September 21st, 2017 5:28am MDT

The temperature roller coaster that we have seen for the past week climbs back up today with highs more than 10 degrees above normal expected. There will be plenty of sun and also some breezy winds to go along with the warm temps.

The day starts with clear skies and will remain that way for the most part through the day. The afternoon may bring a few light clouds but nothing that will block the sun for any length of time. We will be seeing winds picking up speed by the late morning and lasting into the evening. Fire danger remains quite high.

Temperatures will steadily climb toward a high today around 88 degrees. Denver’s record high for today’s date is 89 degrees, set in 2015, so we will be coming close.

Tonight, look for winds to calm, skies to remain clear and temperatures to dip to around 53 degrees.

Live conditions here.

Join the Discussion - Post your commentJoin the Discussion!

Hurricane Maria unleashes fury on Puerto Rico: ‘The winds are like out of a horror movie’

Wednesday, September 20th, 2017 11:19am MDT

SAN JUAN, Puerto Rico — A ferocious Hurricane Maria slammed Puerto Rico just before dawn Wednesday as some 3.5 million people girded for a day of vicious winds and drenching rain expected to devastate the American territory. The eye of the storm made official landfall at 6:15 a.m. near Yabucoa, about 45 miles southeast of the… » Click here to read the rest of Hurricane Maria unleashes fury on Puerto Rico: ‘The winds are like out of a horror movie’

Join the Discussion - Post your commentJoin the Discussion!

Lots of sun, less wind, comfortable temps for Wednesday

Wednesday, September 20th, 2017 5:32am MDT

Summer is quickly coming to a close and as it does, we are set to enjoy a pleasant day today. Temperatures will be a bit above normal but not particularly warm and there will be lots of sun to go with it.

Look for sunny to mostly sunny skies throughout the day with few clouds to block those beautiful Colorado skies. Winds will be light and out of the southeast, overall conditions calm and dry. High temperatures today will reach to around the 80 degree mark, perhaps a couple of degrees above.

Tonight, mostly clear skies will be above and lows near 50 degrees.

Join the Discussion - Post your commentJoin the Discussion!

Huge Earthquake Rocks Mexico City

Wednesday, September 20th, 2017 4:27am MDT

The death toll continues to rise following a massive 7.1 magnitude earthquake that struck Mexico City Tuesday afternoon, collapsing buildings, killing at least 248 people and trapping an unknown number of others in the wreckage. The head of Mexico’s civil defense agency, Luis Felipe Puente, said on Twitter 117 deaths were reported in Mexico City, 72… » Click here to read the rest of Huge Earthquake Rocks Mexico City

Join the Discussion - Post your commentJoin the Discussion!

Puerto Rico Braces for Impact of Hurricane Maria

Tuesday, September 19th, 2017 3:32pm MDT

Puerto Rico was spared the worst of Hurricane Irma, which grazed the island and caused huge power blackouts but did not ravage the U.S. territory in the same way it did other islands. That will not be the case with Hurricane Maria, according to forecasters. The category 5 storm is barrelling towards Puerto Rico with winds… » Click here to read the rest of Puerto Rico Braces for Impact of Hurricane Maria

Join the Discussion - Post your commentJoin the Discussion!

Thornton’s Tuesday brings very warm temps, high fire danger

Tuesday, September 19th, 2017 5:03am MDT

Our temperatures rebound today and climb to about 10 degrees above normal. More notable, will be high fire danger brought on by gusty winds and low humidity.

We start the day with sunny skies and other than a few clouds in the afternoon, the view will be largely unobstructed. Temperatures start out cool but then will begin a steady climb with highs in the mid to upper 80s, well above the average of 77 degrees for today.

An approaching trough is going to bring on gusty winds by late morning that will last into the evening. Coupled with low humidity and tinder dry fuels, the fire danger is very high.

The National Weather Service has issued a Red Flag Warning that is in effect from 11:00am to 8:00pm. Any fires that do get started could see rapid growth and extreme fire behavior. Please be very careful!  Read the complete text of the warning here.

Winds will die down tonight with skies remaining mostly clear. Lows will be dipping to around 50 degrees.

Join the Discussion - Post your commentJoin the Discussion!

September 17 to September 23: This week in Denver weather history

Monday, September 18th, 2017 5:02am MDT
This Week In Denver Weather History

September 17 to September 23: This week in Denver weather history

The calendar may still say it is summer for a few more days but our look back at this week in Denver weather history shows that Old Man Winter can still make an appearance.

From the National Weather Service:


In 2000…unusually hot weather for so late in the season occurred when temperatures climbed into the 90’s setting daily record maximum temperatures on each of the 3 days. The high temperature was 92 degrees on the 15th and 95 degrees on both the 16th and 17th.


In 1906…rain on 5 consecutive days totaled 1.61 inches. A thunderstorm occurred on the 17th. High temperatures ranged from 48 degrees on the 16th to 65 degrees on the 15th. Low temperatures were in the lower to mid 40’s.


In 1971…a record breaking early fall snow storm caused extensive damage to trees and utility lines. The heavy wet snow occurred with little wind…but caused record breaking cold temperatures for so early in the season. Snowfall totaled 15.6 inches at Stapleton International Airport with most of the snowfall…12.0 inches…occurring on the 17th. This was the heaviest first snow of the season. The maximum snow depth on the ground was 13 inches. Record low temperatures were set on three consecutive days: 31 degrees on the 17th…23 degrees on the 18th…and 20 degrees on the 19th…which was also a new all-time record minimum for the month at that time. Record low maximum temperatures were set on 4 consecutive days: 48 degrees on the 16th…35 degrees on the 17th…40 degrees on the 18th… And 42 degrees on the 19th.


In 1873…brisk west to northwest winds at different times during the day…generally in sudden gusts…spread a good deal of dust into the city.

In 1953…strong winds caused thousands of dollars in damage to Boulder. The winds blew for most of the day with great gustiness…and a freak twister was reported during the afternoon. Damage was minor. A thunderstorm wind gust to 40 mph caused some blowing dust at Stapleton Airport.

In 1992…a tornado touched down briefly near Bennett. No damage was reported.

In 1993…severe thunderstorms rumbled across northern portions of metro Denver. Hail as large as 1 3/4 inches in diameter fell in Brighton. Dime size hail damaged several roofs of residences in Lafayette.

In 2000…for the second day in a row…the high temperature of 95 degrees at Denver International Airport broke three record temperature extremes: the high temperature broke the previous record for the day of 94 degrees set in 1895; it marked the warmest it has been for so late in the season; it also marked the 61st day in the year that the temperature had equaled or exceeded 90 degrees…eclipsing the record equaled the previous day and first set on September 29… 1994.


In 1901…northeast winds were sustained to 42 mph with gusts to 50 mph behind an apparent cold front.

In 1948…the low temperature cooled to only 69 degrees…the all-time record high minimum for the month.

In 1988…a strong cold front blasted metro Denver with high winds. Gusts reached 82 mph in Longmont and 81 mph at Jefferson County Airport near Broomfield where the winds flipped over and destroyed a small airplane. Wind gusts to 60 mph were recorded in Boulder and Wheat Ridge. West wind gusts to 54 mph were clocked at Stapleton International Airport. The strong winds downed trees and power lines and damaged homes and cars. A Longmont man was slightly injured…when a tree fell on top of his car.

In 1990…a slow moving thunderstorm over southwest metro Denver spawned an ominous looking funnel cloud near the intersection of Sheridan Blvd. and U.S. Highway 285. The funnel cloud nearly touched down a few times before lifting back into the main cloud. No damage was reported. Pea to marble size hail and 3/4 inch of rain fell over central and northeast Denver. Numerous streets and underpasses became flooded on Denver’s south side when the heavy runoff backed up storm sewers. Thunderstorm rainfall totaled 1.02 inches at Stapleton International Airport.

In 1993…a severe thunderstorm rolled through southeast metro Denver. Dime size hail was reported in many areas. Straight-line winds from the thunderstorm…measured by a weather spotter at 70 mph…tore the roof off 6 apartments of an apartment complex in Aurora. Heavy rain which accompanied the winds caused major damage to the apartments as well as the contents. Many trees…fences… And power poles were knocked down by the strong winds. Heavy rain flooded roadways in Denver and Aurora. Thunderstorm rainfall totaled 1.08 inches and north winds gusted to 44 mph at Stapleton International Airport where the visibility was briefly reduced to as low as 1/4 mile in heavy rain.

In 1996…a late summer snowstorm struck the northern mountains and Front Range eastern foothills. Golden Gate Canyon received 6 inches of new snow with 5 inches reported at both Nederland and Blackhawk. Thunderstorms produced heavy rain across metro Denver…which was mixed with snow by late evening. Rainfall totaled 0.83 inch at the site of the former Stapleton International Airport and 1.22 inches at Denver International Airport where northwest winds gusted to 39 mph.


In 1955…heavy rains caused flash flooding across portions of metro Denver. Rainfall totaled 1.71 inches at Stapleton Airport.


In 1955…hail stones to 2 1/2 inches in diameter were reported north of Denver. The large stones broke many automobile windshields.

In 1963…hail to 3/4 inch in diameter fell in Westminster.

In 1983…an unusually strong cold front roared through metro Denver during the afternoon hours. At Stapleton International Airport…the temperature dropped 51 degrees… From a sunny 86 degrees to a snowy 35 degrees…in just 7 hours. Strong winds and a wall of blowing dust followed the front. Northeast winds gusting to 36 mph briefly reduced the surface visibility to 1 mile in blowing dust at Stapleton International Airport where only a trace of snow fell later.

In 1996…high winds gusting to 84 mph were measured at Golden Gate Canyon in the foothills west of Denver. West winds gusted to only 25 mph at Denver International Airport.

20 » Click here to read the rest of September 17 to September 23: This week in Denver weather history

Join the Discussion - Post your commentJoin the Discussion!