Thornton, Colorado, USA
UpdatedSat, 20-Jul-2019 12:00am MDT 


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Unseasonably warm temperatures Wednesday, isolated thunderstorms possible

Wednesday, May 15th, 2019 5:01am MDT

Today’s weather will be a virtual carbon copy of what we have seen the last two days. The one key difference? Temperatures will be climbing even higher.

Mostly sunny skies will be above through the morning then in the afternoon we will see periods of some higher clouds.

Those clouds may help bring an isolated thunderstorm or two. Like the last couple of days though, these will likely be dry with gusty winds being the most notable feature.

Temperatures today in Thornton will be topping out in the mid-80s, well above the average high for the date of 71 degrees.

Tonight, partly clear skies will be above with lows in the low 50s.

Keep an eye on the temperature with our live #weather gauges here.

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Temps well above normal, slight chance for a thunderstorm on Tuesday

Tuesday, May 14th, 2019 4:56am MDT

You would have a hard time differentiating today’s forecast from what we saw yesterday. We will again have unseasonably warm temperatures, a good dose of sun and just a slight chance for a thunderstorm in the afternoon.

The day starts with sunny to mostly sunny skies and the same will be above until this afternoon. Clouds will increase a bit after noon as moisture increases. That will usher in a slight chance for a thunderstorm in the mid-afternoon but, like yesterday, any that develop are expected to bring not much more than gusty winds. High temperatures today will top out around 82 degrees, 12 degrees above the average high for the date.

Tonight, partly cloudy skies will be above with lows dropping to around 50 degrees.

Keep an eye on those temperatures here.

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Monday to offer up unseasonably warm temps, slight chance for a thunderstorm

Monday, May 13th, 2019 5:07am MDT

Thornton gets its workweek started with temperatures a good bit above normal. Similarly mild conditions will be seen for the coming days as well.

Mostly sunny skies start us off today and will be with us through the early afternoon. After that, we may see some clouds move in signaling a slight chance for some high-based thunderstorm activity. Right now it looks like if there are any storms, they will be isolated and primarily just offer up some gusty winds. Temperatures will top out in the upper 70s, perhaps hit the 80 degree mark.

Tonight, partly cloudy skies will be above with lows around 50 degrees.

Looking at the rest of the workweek, unseasonably warm temperatures will be with us until Friday. After that, we may see a couple of systems move through to cool things down this weekend. More in the extended weather forecast here.

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Thornton’s weekend weather sees a return toward warmer temps, drier conditions

Friday, May 10th, 2019 5:06am MDT

After a few very damp and chilly days, our preferred springtime weather conditions stage a return. We do start out cooler than normal but by the end of the weekend will be seeing lots of sun and seasonal temperatures.

For today, we start out with mostly cloudy skies above and while it will ease some through the day, there will be more clouds than blue sky. Temperatures will top out in the mid-50s, a big improvement over yesterday but cooler than normal. Mid-afternoon into the evening brings just a slight chance for a thunderstorm. Overnight lows tonight will dip to the mid-30s.

Saturday continues to warm up and dry out. Highs will be in the mid-60s with sunny skies initially then a few clouds later in the day. Only the slight chance for a thunderstorm is seen. Saturday night into Sunday morning, partly cloudy skies will be above and temperatures will drop to around 40 degrees.

Mother’s Day will offer the nicest and warmest day of the three day period. Look for sunny to mostly sunny skies throughout the day with highs near 70. Have a great weekend!

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Snow and rain, chilly temperatures for Thornton’s Thursday

Thursday, May 9th, 2019 5:06am MDT

Not the spring-like weather we would hope or expect to see this time of year. We will continue to feel the effects of the passing storm as temperatures will be well below normal and snow and rain will be seen for parts of the day.

We start out with light snow falling and will continue to see that until mid-morning when we switch back to rain in the afternoon. Light accumulations will be seen on grassy areas.

Cloudy skies will be above for most of the day but there may be just a slight break in the cloud cover in the late afternoon and evening.

Temperatures are starting out right at the freezing mark and will warm to the low 40s.

Tonight, some scattered rain showers will be seen, perhaps some light snow but with little, if any accumulation. Overnight lows will again dip to near freezing.

A Freeze Watch will remain in effect until 9:00am Friday. Sensitive vegetation may be damaged by the cold and roads may be icy in spots early this morning and overnight tonight.

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Wednesday’s weather to offer cool, damp conditions; snow possible tonight

Wednesday, May 8th, 2019 5:03am MDT

Springtime in Colorado can offer up just about anything. We’ve gone from clear, mild conditions this past weekend to a taste of severe weather Monday and now we may be seeing a taste of wintry weather.

The day starts off with some light drizzle and areas of fog. A Dense Fog Advisory is in effect until 9:00am so please be aware and slow down if you encounter any fog. Cloudy skies will be the rule today throughout.

Winds will become a bit breezy, particularly in the mid-afternoon. Temperatures will be well-below normal with highs today only in the mid-40s. There will be periods of light rain throughout the day.

Tonight, temperatures are going to drop to near freezing and that looks to allow the precipitation to change over to snow. We may very well see an inch or two on grassy areas before dawn tomorrow.

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May 5 to May 11: This Week in Denver Weather History

Tuesday, May 7th, 2019 4:00pm MDT
This week in Denver weather history

May 5 to May 11: This Week in Denver Weather History

This time of year the focus is usually on spring severe weather with lightning, tornadoes and hail being the highlight. Our look back at this week in Denver weather history shows many of those types of events. Also notable are the few, unusually late in the season snow events, some of which were quite heavy.

From the National Weather Service:


In 1898…snowfall totaled 15.5 inches in downtown Denver. Most of the snow…6.2 inches…fell on the 3rd. Most of the snow melted as it fell. The greatest snow depth on the ground was only 2.5 inches on the 3rd at 8:00 pm. This was the only snowfall during the month. Northeast winds were sustained to 22 mph on the 1st.


In 2001…a very slow moving pacific storm system became parked near the four corners region…which allowed heavy snow to develop above 6500 feet in the foothills with a mix of rain and snow over lower elevations of metro Denver. Snowfall totals included: 21 inches atop Crow Hill and at Idaho Springs; 19 inches near Blackhawk; and 18 inches in Coal Creek Canyon…Genesee…and 11 miles southwest of Morrison. Snowfall totaled 6.2 inches at the site of the former Stapleton International Airport. Precipitation (rain and melted snow) totaled 2.09 inches at Denver International Airport where north winds gusted to 30 mph on the 2nd.


In 1908…rain changed to snow on the evening of the 3rd and continued through the early evening of the 5th. Snowfall totaled 10.0 inches over downtown Denver. This was the last measurable snow of the season. Precipitation totaled 1.51 inches. North winds were sustained to 23 mph on the 3rd…33 mph on the 4th…and 21 mph on the 5th. Three temperature records were set. High temperatures of 30 degrees on the 4th and 38 degrees on the 5th were record low maximum temperatures for the dates. The reading on the 4th was also the all-time record low maximum for the month of May.

In 2007…a slow moving pacific storm system…from the desert southwest…brought a period of unsettled weather to the region. During the 3-day period…locally heavy snow was reported over parts of the Front Range foothills. Storm totals included: 15 inches near Conifer…14.5 inches west of Jamestown…13.5 inches; 6 miles southwest of Evergreen…and 12.5 inches at pine junction. Severe thunderstorms…producing large hail…up to one inch in diameter were observed in the vicinity of Boulder and Hudson. Lightning struck a residence in Jefferson County. The roof was hit…causing the attic to catch fire. At Denver International Airport…lightning struck a United Airlines jet as it was pushing away from the gate. The passengers were taken off the jet and put on another plane.


In 1986…high winds buffeted the foothills. Wind speeds of 60 to 75 mph were recorded in Boulder. At Stapleton International Airport…west winds gusted to 45 mph on the 4th and to 40 mph on the 5th.

In 2000…a brief warm spell resulted in setting two daily high temperature records. The temperature climbed to highs of 87 degrees on the 4th and 89 degrees on the 5th.


In 1969…heavy rains caused flooding on Boulder creek in Boulder…which resulted in one death on the 7th. Flooding also occurred on bear creek in Sheridan and on the South Platte River in Denver. Rain over most of the eastern foothills started late on the 4th and continued with only brief interruptions in many areas until the morning of the 8th. Very high rates of rainfall occurred on the 6th and 7th with the greatest intensities in a band along the foothills from about 25 miles southwest of Denver northward to Estes Park. Storm totals by both official and unofficial measurements exceeded 10 inches over much of this area and were over 12 inches in some localities. Heavy snow fell in the higher mountains and in the foothills later in the period. The saturation of the soil resulted in numerous rock and landslides…and the heavy run-off caused severe damage along many streams and flooding on the South Platte River. Many foothill communities were isolated as highways were blocked and communications disrupted. Roads were severely damaged over a wide area…and a large number of bridges washed out. Many roads were closed due to the danger from falling rocks. A building in Georgetown collapsed from the weight of heavy wet snow. In Boulder…a man drowned when caught by the flooding waters of Boulder Creek…and a patrolman was injured. Rainfall totaled 7.60 inches in Boulder with 9.34 inches recorded at the Public Service Company electric plant in Boulder Canyon. In Morrison…rainfall totaled 11.27 inches in 4 days. Heavy rainfall totaled 4.68 inches at Stapleton International Airport over 3 days from the 5th through the 7th. Rainfall of 3.14 inches was recorded in 24 hours on the 6th and 7th. Downstream flooding continued along the South Platte River until the 12th when the flood crest reached the Nebraska line.


In 1903…apparent post-frontal northeast winds were sustained to 48 mph with gusts to 60 mph.

In 1950…a northwest wind gust to 52 mph was recorded at Stapleton Airport.

In 1969…a funnel cloud was observed for 2 to 3 minutes just north of Parker. Two other funnel clouds were sighted in the same area. The public sighted a tornado 15 miles east of Stapleton International Airport. No damage was reported.


In 1907…rain changed to snow on the 5th…continued through the night…and totaled 3.50 inches. Northeast winds were sustained to 15 mph on the 5th.

In 1917…post-frontal rain changed to heavy snow and totaled 12.5 inches over downtown Denver. Most of the snow… 12.0 inches…fell on the 5th and this was the greatest 24-hour snowfall ever measured during the month of May. This was also the only measurable snow of the month that year. Low temperatures of 27 degrees on the 5th and 23 degrees on the 6th were record minimums for the dates. High temperatures on both days were in the lower 40’s. Southeast winds were sustained to 24 mph with an extreme velocity to 26 mph.

In 1964…high winds gusted to 54 mph in Boulder and to 80 mph at Jefferson County Airport near Broomfield. Wind gusts of 50 to 60 mph were common over all of eastern Colorado. Buildings…power lines…trees…and vehicles were damaged by the wind. South-southwest wind gusts to 54 mph caused some blowing dust at Stapleton International Airport where the visibility was briefly reduced to 2 miles.

In 1973…a heavy driving rain storm with embedded thunderstorms…produced 1 to 5 inches of rain and caused local flash flooding along the east slopes of the Front Range. The greatest flash flooding occurred in metro Denver where rainfall totaled 3.56 inches at Stapleton International Airport. Flooding in metro Denver occurred on Clear Creek and the South Platte River…already swollen from heavy snowmelt. Numerous basements were flooded… Roads and streets were washed out…a bridge was demolished… And miscellaneous other damage was reported. North winds gusted to 39 mph at Stapleton International Airport during the storm. The storm produced major downstream flooding along the South Platte River all the way to the Nebraska border during the next two weeks. One person died and total damage was estimated at around 120 million dollars.

In 1978…heavy wet snow of around 24 inches collapsed an office and hotel building in Boulder. Many cars were abandoned in the city. Denver received 14 inches of heavy wet snow with Evergreen and Golden reporting 12 inches. Snowfall totaled 12.4 inches at Stapleton International Airport with a total accumulation of snow on the ground of 8 inches due to melting. Southeast winds gusted to 23 mph on the 5th. Temperatures both days remained in the lower to mid-30’s.

6 » Click here to read the rest of May 5 to May 11: This Week in Denver Weather History

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Thornton’s Tuesday to feature cooler temperatures, clouds and showers

Tuesday, May 7th, 2019 5:07am MDT

Yesterday we received our first taste of springtime thunderstorms of the season. Today things cool down, stay damp and may deliver some more excitement.

Things start off with a Dense Fog Advisory in effect until 8:00am. It will be a bit patchy but be aware that conditions may be hazardous in some spots. Cloudy skies will be above through much of the day but some blue may, briefly sneak in at different points.

Temperatures today will be largely dependent on the clouds. If they are dense, we may have a hard time reaching the forecast high. Right now we are expecting temps to top out in the mid-50s but they may fall short.

A few, scattered, light showers may be seen this morning but nothing that will amount to much. This afternoon brings a much better chance for showers and thunderstorms, particularly after 3:00pm.

How strong activity is will depend greatly on the aforementioned temperatures. Warmer readings would aid convection and generate stronger storms. Cooler temps will keep things more stable and calm.

Tonight, some light showers will be possible through the night. Look for lows down to about 40 degrees.

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Cooler temperatures, chance for thunderstorms start Thornton’s workweek

Monday, May 6th, 2019 4:59am MDT

The first of a series of systems that will be impacting our weather through the week arrives today. With it, temperatures cool to around normal and we see a bit of chance for a thunderstorm.

Cloudy skies start things off then we will see some improvement later in the morning. Clouds will then increase again in the afternoon.

Temperatures will head toward a high in the mid-60s, near the average for the date of 66 degrees.

Some scattered thunderstorms will develop this afternoon with our best chance coming in the late afternoon and evening from about 5:00pm to 8:00pm.

Light rain showers with a bit of thunder will be possible till midnight then we see just some light rain after that. Overnight lows tonight will dip to the mid-40s.

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

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April 2019 weather recap: Warmer, drier than normal for Thornton

Sunday, May 5th, 2019 6:43am MDT

The month of April had the usual, inconsistent weather conditions we expect from the month. Thornton enjoyed everything from spring-like days with mild temperatures to a healthy round of snow and cold.

The month started out mild with seven of the first nine days of the month seeing above normal temperatures and pleasant conditions. A cold front and storm system moved in on the 10th though and brought about significant changes for a few days and our first snow of the month.

Warmer weather returned though and on the 20th we recorded our first 80 degree day of the year. Showers and thunderstorms on the 21st brought some much-needed rain then we dried back out for the next six days. We saw a couple more 80+ degree days then the final two days chilled things out and delivered a bit more snow.

Thornton’s overall average temperature for the month came in at 49.6 degrees. This was a good bit above Denver’s long-term April average of 47.4 degrees. Out at DIA where the Mile High City’s official measurements are kept, the average temperature was similar with 49.1 degrees.

Temperatures in Thornton ranged from a high of 81.4 degrees on the 26th down to a low of 17.5 degrees on the 11th. Denver saw a high reading of 80 degrees on the 20th and a low of 17 on the 11th.

In terms of precipitation, Denver averages 1.71 inches during April. Both Thornton and Denver fell short of that mark with 0.78 inches and 1.25 inches in their rain buckets respectively.

Snowfall in Thornton was respectable with 8.1 inches of the white stuff. Denver was well short of that with 3.5 inches. April averages 6.8 inches so while Thornton was above that, Denver was below.

Click here to view Thornton’s April 2019 climate report.

Thornton, Colorado's April 2019 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s April 2019 temperature summary. (ThorntonWeather.com)

Thornton, Colorado's April 2019 precipitation summary. (ThorntonWeather.com)

Thornton, Colorado’s April 2019 precipitation summary. (ThorntonWeather.com)

913 AM MDT WED MAY 1 2019




                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
 HIGH              90   04/30/1992
 LOW               -2   04/02/1975
HIGHEST            80   04/20                         83  04/29
LOWEST             17   04/11                         21  04/06
AVG. MAXIMUM     62.7              61.5     1.2     63.2
AVG. MINIMUM     35.6              33.3     2.3     32.5
MEAN             49.1              47.4     1.7     47.8
DAYS MAX >= 90      0               0.0     0.0        0
DAYS MAX <= 32      0               0.3    -0.3        0
DAYS MIN <= 32     10              13.0    -3.0       16
DAYS MIN <= 0       0               0.0     0.0        0

 MAXIMUM         8.24   1900
 MINIMUM         0.03   1963
TOTALS           1.25              1.71   -0.46     0.86
DAILY AVG.       0.04              0.06   -0.02     0.03
DAYS >= .01         9               9.1    -0.1        8
DAYS >= .10         2               4.5    -2.5        4
DAYS >= .50         1               0.9     0.1        0
DAYS >= 1.00        0               0.5    -0.5        0
 24 HR. TOTAL    0.82   04/21 TO 04/21           04/21 TO 04/21

 TOTAL            3.5               6.8
RECORD APRIL     33.8    1933

HEATING TOTAL     469               529     -60      509
 SINCE 7/1       5805              5731      74     5250
COOLING TOTAL       0                 1      -1        2
 SINCE 1/1          0                 1      -1        2

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

AVERAGE WIND SPEED              10.3

AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            2
NUMBER OF DAYS PC             19


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