Thornton, Colorado, USA
UpdatedWed, 13-Dec-2017 12:20am MST 


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October 8 to October 14: This week in Denver weather history

Wednesday, October 11th, 2017 12:34pm MST
This Week In Denver Weather History

October 9 to October 14: This Week in Denver Weather History

Denver has yet to get a taste of wintry weather this year as we continue what has been a very dry period the last few months. In the past that hasn’t always been the case and our look back at this week in Denver weather history shows that heavy, winter-like snowstorms can and do strike in October.

From the National Weather Service:


In 1990…the season’s first snow occurred. Snowfall amounts varied from 3 to 7 inches across metro Denver. Snowfall totaled 4.0 inches at Stapleton International Airport where north winds gusted to 29 mph.


In 1923…southeast winds were sustained to 44 mph with gusts to 47 mph. The strong winds persisted through the afternoon. The high temperature of 77 degrees was the warmest of the month that year.

In 1975…a wind gust to near 100 mph was recorded in Boulder. Frequent wind gusts to 60 mph were reported along the foothills causing only minor damage. West winds gusted to 45 mph at Stapleton International Airport.


In 1910…light smoke from forest fires in the mountains was sighted over the city.

In 1982…northwest winds gusted to 49 mph at Stapleton International Airport.


In 2005…a major winter storm brought heavy…wet snowfall to the Front Range mountains…eastern foothills…portions of metro Denver…and the Palmer Divide. Snow accumulations ranged from 8 to 26 inches with drifts from 3 to 4 feet in places. The heaviest snow occurred to the east and southeast of the city…closing most major highways in that area…including I-70 from Denver to Limon. The Red Cross opened four shelters for people who were stranded along I-70 in eastern Colorado. Since many trees had not yet shed their leaves…the storm caused significant tree damage. One woman in Denver was killed when a tree branch… 8 to 10 inches in diameter…snapped under the weight of the heavy…wet snow and struck her as she was shoveling her driveway. Xcel Energy reported power outages to about 35 thousand customers. Several incoming flights were delayed at Denver International Airport. Snow totals included: 16 inches in the foothills near Boulder…12 inches at Genesee and near Golden…22 inches near Watkins…19 inches near Bennett…17 inches southeast of Aurora…14 inches near Parker…13 inches near Castle Rock…12 inches in centennial… 11 inches in Parker…and 10 inches at Denver International Airport and in Littleton. While many areas of metro Denver received heavy snow…others experienced almost entirely rain. This included west and northwest metro Denver…Boulder…and Longmont. Rainfall amounts were significant as storm totals ranged between 1.50 and 2.50 inches. The steady rainfall triggered 3 rockslides in foothills canyons. Two of the slides occurred on State Highway 119 in Boulder Canyon and the longest slide…7 feet in length…on State Highway 74 in Bear Creek Canyon at Idledale. North winds were sustained to around 23 mph with gusts to 31 mph at Denver International Airport on the 9th. The high temperature of only 34 degrees on the 10th was a record low maximum for the date. The low temperature on both days was 32 degrees.


In 1901…an evening thunderstorm produced east winds to 43 mph with gusts to 48 mph.

In 1949…strong winds believed to be the worst in Boulder’s history at the time caused over 100 thousand dollars damage in the city. Peak winds were estimated to 85 mph at Valmont…just east of Boulder. High winds also occurred over most of metro Denver and caused damage to trees…window glass…and utility lines. The damage was most pronounced over the northwest metro area…including north Denver and Lakewood. Falling tree branches caused damage to parked autos and houses. Wind gusts to 70 mph were recorded at Stapleton Airport.

In 1964…lightning struck and killed a 13-year-old boy…while he was riding his bicycle along a tree-lined residential street in south Denver. Apparent microburst winds gusted to 54 mph at Stapleton International Airport.


In 1986…the first significant snowstorm of the season produced 2 to 5 inches of snow over metro Denver with 5 to 10 inches in the foothills west of Denver. Wondervu recorded the most snow from the storm…13 inches. The heavy wet snow caused numerous power outages. The storm was accompanied by strong north winds with gusts to 41 mph recorded on the 10th. The first snowfall of the season totaled 3.1 inches at Stapleton International Airport with only one inch on the ground due to melting. The strong cold front accompanying the storm cooled the temperature from a high of 73 degrees on the 10th to a high of only 33 degrees on the 11th…which was a record low maximum for the date.


In 1969…the second heavy snowstorm in less than a week dumped nearly a foot of snow across metro Denver and plunged the area into extremely cold temperatures for so early in the season. Snowfall totaled 11.0 inches at Stapleton International Airport. North winds gusting to 26 mph produced drifts up to 2 feet deep. Temperatures dipped from a high of 52 degrees on the 10th to a record low for the date of 10 degrees on the 12th. There was additional damage to trees and power and telephone lines from heavy snow accumulations and icing. Travel was restricted or blocked by drifting snow in both the mountains and on the plains east of Denver.


In 1997…damaging winds ahead of an approaching storm system developed in the foothills and spread across metro Denver. Winds gusted to 88 mph at conifer…71 mph at the National Center for Atmospheric Research on the mesa in Boulder… And 53 mph at Denver International Airport. Several trees and street signs were blown down with scattered power outages reported throughout metro Denver. In Arvada…a car window was blown out by a strong wind gust.

In 2013…high winds occurred in and near the Front Range Foothills. Peak gusts included: 85 mph at Rooney Road…84 mph…2 miles south of Marshall; 82 mph at Rocky Flats National Wind Technology Center and Wondervu; 79 mph at the Mesa Lab at NCAR and 75 mph…3 miles south-southwest of Boulder; 73 mph in Superior and 68 mph in Golden. The wind downed trees and power lines. As a result…scattered electrical outages affected 20000 Xcel Energy customers through the morning hours. The main outages affected the cities of Boulder…Golden and Lakewood. Smaller outages were reported in areas of Gold Hill…Ward… Westminster and Wheat Ridge.

» Click here to read the rest of October 8 to October 14: This week in Denver weather history

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Wednesday to offer seasonal temperatures, lots of sun

Wednesday, October 11th, 2017 4:54am MST

A largely ‘normal’ October day ahead for Thornton. Temperatures should top out right near average for the date and we will see lots of sun and calm conditions.

The day starts with sunny skies and other than a few clouds this afternoon, the view above will be dominated by those beautiful blue Colorado skies. Temperatures start out quite chilly early but then we will see a steady warm up toward a high of 67 degrees.

Tonight, skies remain mostly clear and lows will dip to the mid-40s.

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More than 5,000 homes evacuated as Orange County fire grows to 6,000 acres

Wednesday, October 11th, 2017 3:03am MST

LOS ANGELES — A wind-fed wildfire surged over the Anaheim Hills on Monday, burning several homes and forcing thousands to evacuate as fire crews struggled to battle the rapidly growing blaze. The fire broke out around 9:20 a.m. near the 91 Freeway and Gypsum Canyon Road, and quickly leaped the California 241 toll road. It raced… » Click here to read the rest of More than 5,000 homes evacuated as Orange County fire grows to 6,000 acres

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Lots of sun, warmer temperatures for Thornton’s Tuesday

Tuesday, October 10th, 2017 4:58am MST

Lots of sun, warmer temperatures for Thornton’s Tuesday. The storm system that brought our first snow of the season has moved out. In its wake we start out cold but then will see a nice little warmup although temps will still be below normal.

We start out the day with sunny skies and can expect largely cloudless skies above throughout the day. Early morning temperatures below freezing will warm with the rising sun and head toward a high in the mid-50s. That’s a 20 degree improvement over yesterday but well below the average for the date of 68 degrees. Otherwise, conditions will be calm and dry.

Tonight mostly clear skies will be above and lows in the mid-30s.

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Engineers: Lives Lost in Mexico Quake Could Have Been Saved

Monday, October 9th, 2017 6:03pm MST

Nearly two-thirds of the buildings that collapsed in Mexico City’s monstrous earthquake last month were built using a construction method that is now forbidden in seismic hotspots in the United States, Chile and New Zealand, according to new data compiled by a team of structural engineers at Stanford University. The suspect building technique called flat slab… » Click here to read the rest of Engineers: Lives Lost in Mexico Quake Could Have Been Saved

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Cold and wet Monday as Thornton gets its first wintry blast of the season

Monday, October 9th, 2017 5:07am MST

From sun and warmth the past two days to cold and snow today. The changeover to snow occurred later than expected and thus totals will not quite be what was expected but we will be very wet and quite cold.

As of this writing nearly a half inch of liquid precipitation has been received since the storm arrived yesterday evening, most of which fell as rain. Early this morning it has transitioned to snow and we are seeing some light, slushy accumulations. Roads are extraordinarily wet with all the water and some spots may become slick with the cold temperatures.

Look for the snow, with some rain at times, to continue through the morning hours before tapering off after noon. We could still see total accumulations of a couple of inches, primarily on grassy areas.

Temperatures will only reach highs in the mid-30s. A Winter Storm Warning remains in effect until 3:00pm although it will likely be dropped before that time.

Skies will begin clearing by the late afternoon / evening and by midnight be mostly clear. Lows tonight will be right near the freezing mark. A Freeze Warning remains in effect until 10:00am tomorrow.

Editor’s note: The image below has the correct forecast high temperature.  It should read 35 degrees.

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Breaking: Sunday remains warm but Winter Storm and Freeze Warnings issued for tonight & tomorrow

Sunday, October 8th, 2017 5:59am MST

Get out and enjoy that warm weather today because we are set to get a healthy dose of wintry weather tonight. The storm that we have been mentioning for days is closing in and warnings have been posted for very cold temperatures and decent snow accumulations.

For today, look for sunny skies to start things off then by mid to late morning a gradual increase in cloud cover will occur. Winds will be light through about mid-afternoon when we reach our high in the low to mid-70s.

After that, the front pushes through and wind speeds will being increasing and by this evening gusts in excess of 40mph will be possible. After about 6:00pm some light rain may be seen with better chances after 9:00pm.

The temperature will then be well on its way downward and a transition to snow looks to occur around 11:00pm or so. The snow is then expected to continue through tomorrow morning.

Total accumulations in our area could be on the order of 3 to 5 inches, some localized amounts may be higher. Certainly given how warm the ground is, some of what initially falls will simply melt off. Lows tonight will be right near the freezing mark.

The National Weather Service has issued a Freeze Warning that is in effect from midnight tonight to 10:00am Tuesday. Additionally, a Winter Storm Warning is in effect from midnight tonight to 3:00pm.

Use the warm weather today to ensure you, your home and your vehicles are prepared for this significant change in the weather.

Read the full text of the warnings here.

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A very mild Saturday for Thornton but a Winter Storm Watch is issued for Monday

Saturday, October 7th, 2017 6:29am MST

The next few days will feature the crazy swings in weather we can experience here in Thornton. We will enjoy unseasonably warm conditions today and tomorrow but tomorrow night a potent storm arrives and is expected to bring a decent accumulating snow event.

For today, look for sunny skies throughout the day. Temperatures will be warming to a high right near the 80 degree mark. Some gusty winds will be on tap for the afternoon, lasting into the early evening. Tonight the winds settle down, skies remain clear and lows will be in the mid-40s.

Tomorrow look for similarly sunny and dry conditions but it will be cooler with highs in the low 70s.

The storm moves through Sunday night and after midnight any precipitation is expected to change to snow. Assuming temperatures remain cold enough, snow will continue into late Monday morning. The National Weather Service has issued a Winter Storm Watch that will run from midnight Sunday night to 6:00pm Monday. Total accumulations of 4 to 6 inches will be possible although a good bit of that will likely melt on contact. Certainly you should be prepared for a potentially rough commute Monday AM. Our Winter Weather Briefing has the latest.

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Following an unsettled Friday, Thornton’s weekend to warm up, offer pleasant conditions

Friday, October 6th, 2017 5:24am MST

Not too bad of a looking three day period for us. Today will be a bit cool and possibly damp but after that we are going to enjoy a weekend with above normal temps and dry conditions. Then, well, things change considerably with snow being likely Sunday night into Monday.

For today some spots of fog may be seen early then we will have mostly cloudy skies above until the late afternoon / early evening when we should see some clearing. There will be some chances for sprinkles of rain throughout the day with the best opportunity coming in the afternoon. The afternoon will also offer up some breezy northwest winds. Highs today will be in the low to mid-60s.

Tonight look for skies to clear. Overnight lows will be in the mid-40s.

Saturday looks to be the nicest day of the period. Sunny skies will start things off and be with us throughout the day. We will remain dry and see calm conditions as we head for a high temperature around 80 degrees.

Saturday night into Sunday morning skies will be mostly clear with lows in the mid-40s.

The weekend closes out on Sunday with a nice day as well. Sunny skies will be above and while high temperatures will be a bit cooler, they will remain above normal.

The next storm system may begin to make itself felt as early as Sunday evening with a few rain showers being possible. Overnight Sunday night into Monday, if all goes as it looks now, that precipitation will change over to snow. We are still a good ways out from that and there is still uncertainty regarding the timing and speed, both of which will affect the impact of the system.

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September 2017 weather recap: Month starts warm and dry, ends cool and damp

Thursday, October 5th, 2017 12:57pm MST

The month of September 2017 saw significant differences between the start and the end.  The first two-thirds of the month were extraordinarily dry with temperatures well above normal. The last 10 days brought a big change though with damp conditions and much cooler conditions.

High pressure dominated the region for the first few weeks of the month.  During this period when we normally see cooler temperatures, we instead saw highs oftentimes at or above 90 degrees and a couple of record high readings.  Additionally, it was exceedingly dry with Thornton only received 0.03 inches of precipitation through the first 22 days of the month.

Big changes arrived and the last nine days of the month stood it stark contrast to the rest of September. Low pressure and a series of disturbances brought much cooler temperatures and much-needed precipitation, including snowfall in the high country. Seven out of the last eight days saw below normal high temperature readings and enough precipitation fell to push us to just above normal.

Thornton’s overall average temperature for the month came in at 62.4 degrees.  This was a full degree cooler than Denver’s long term September average of 63.4 degrees.  Out at DIA where Denver’s official measurements are taken, it was a good bit warmer with an average temperature of 65.1 degrees.

Temperatures in Thornton ranged from a high of 98.5 degrees on the third and a low of 40.9 degrees on the morning of the 29th.  Denver saw their high of 97 degrees on the third as well and their coldest reading of 40 degrees on the 20th.

Two record high temperatures were officially set or tied for the Mile High City.  The high temperature of 97 degrees on the third tied the record high for the date.  A reading of 92 degrees on the 21st set a new record high for that date.

In terms of precipitation, Denver averages 0.96 inches during September.  Thornton tallied 1.05 inches in the rain bucket while Denver bested us with 1.26 inches.

Click here to view Thornton’s September 2017 climate report.

Thornton, Colorado’s September 2017 Temperature Summary. (ThorntonWeather.com)

Thornton, Colorado’s September 2017 Temperature Summary. (ThorntonWeather.com)

Thornton, Colorado’s September 2017 Precipitation Summary. (ThorntonWeather.com)

Thornton, Colorado’s September 2017 Precipitation Summary. (ThorntonWeather.com)

From the National Weather Service:

244 AM MDT SUN OCT 1 2017




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              97   09/03/2017
 LOW               17   09/29/1985
HIGHEST            97R  09/03        91       6       93  09/05
LOWEST             40   09/20        35       5       37  09/10
AVG. MAXIMUM     79.0              78.5     0.5     82.3
AVG. MINIMUM     51.3              48.3     3.0     49.7
MEAN             65.1              63.4     1.7     66.0
DAYS MAX >= 90      9               3.4     5.6        6
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 1.26 0.96 0.30 0.28 DAILY AVG. 0.04 0.03 0.01 0.01 DAYS >= .01         6               6.5    -0.5        4
DAYS >= .10         2               3.3    -1.3        1
DAYS >= .50         1               0.6     0.4        0
DAYS >= 1.00        0               0.1    -0.1        0
 24 HR. TOTAL    0.83   09/23 TO 09/23           09/12 TO 09/12

 TOTAL             0.0
TOTALS            0.0               1.3

HEATING TOTAL     122               125      -3       64
 SINCE 7/1        130               141     -11       79
COOLING TOTAL     131                76      55       99
 SINCE 1/1        880               764     116      861

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

AVERAGE WIND SPEED              9.6

AVERAGE SKY COVER           0.50
NUMBER OF DAYS FAIR            9
NUMBER OF DAYS PC             15


THUNDERSTORM              0     MIXED PRECIP               0
HEAVY RAIN                1     RAIN                       1
LIGHT RAIN               10     FREEZING RAIN              0
LT FREEZING RAIN          0     HAIL                       0
HEAVY SNOW                0     SNOW                       0
LIGHT SNOW                0     SLEET                      0
FOG                       8     FOG W/VIS <= 1/4 MILE      1
HAZE                     10

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