Category Archives: Climatology

Climatology, Thornton Weather

March 2024 weather recap: Temps near normal and an abundance of moisture

Thornton, Colorado's March 2024 Temperature Summary. (ThorntonWeather.com)
Thornton, Colorado’s March 2024 Temperature Summary. (ThorntonWeather.com)

The month of March started off pretty slow with little weather drama and dry conditions. That changed as we got close to the latter half of the month with precipitation in the form of rain and snow taking over.

Through the first 12 days of the month, we had only received 0.6 inches of snow. We had seen a few days of colder temperatures but generally, mercury readings were above average.

That changed on the 13th. A powerful storm system with an unusual setup arrived. We began with a healthy dose of rain in the evening and then, overnight, the change to snow occurred. Heavy, wet snow fell on the 14th throughout the day and into the evening. Schools and many businesses closed down for the day. Thornton saw 10.8 inches of snow and a whopping 1.73 inches of liquid precipitation.

We then strung together nine days of calm, dry conditions. On the 25th, snow returned although it wasn’t anything too dramatic. Thornton saw 4.4 inches of the white stuff. The month then closed out with temperatures not far from average.

Overall, Thornton saw a monthly average temperature of 42.4 degrees. This was just above our running 18 year average of 42.0 degrees for the month of March. Mercury readings ranged from a high of 71.8 degrees on the 2nd down to 16.8 degrees pm the 26th.

For the Mile High City, where Denver’s official records are taken, they saw an average of 41.4 degrees. That was just slightly cooler than their long term March average of 41.2 degrees.

Liquid precipitation was abundant for the month with Thornton seeing 2.32 inches, most of which came with the storm on the 13th and 14th. This was well above our March average of 1.30 inches.

Denver recorded 1.65 inches in their rain bucket. This too was well above their March average of 0.86 inches.

Snowfall was above average as well. Thornton saw 15.8 inches in March 2024. This easily bested our March average of 11.3 inches.

Our at the airport, Denver saw a mere 9.2 inches. This was a bit above the Mile High City’s long term average for March of 8.8 inches.

Click here to view Thornton’s complete March 2024 climate summary report.

Thornton, Colorado's March 2024 Precipitation Summary. (ThorntonWeather.com)
Thornton, Colorado’s March 2024 Precipitation Summary. (ThorntonWeather.com)
Climatology, Thornton Weather

Thornton’s April 2024 weather preview: Winter, spring and summer all in one month

Thornton's April weather previewApril marks a transition between winter and summer for most of the country but for Denver it is especially true as we can see a stunning variety of weather.

The proverbial April showers are certainly a possibility for Denver. Snow? Tornadoes? Thunderstorms? You bet – all can happen!

For good measure throw in a chance for hail and even dust storms and April gives every type of weather condition you could like – or hate.

Climatology, Thornton Weather

Last week’s snowfall totals from the storm highlight an ongoing issue

Denver's March 14 & 15, 2024 Snowfall Totals. (National Weather Service)
Denver’s March 14 & 15, 2024 Snowfall Totals. (National Weather Service)

We all know our Pi Day storm last week was a big one.

Here in Thornton we recorded 10.8 inches. Downtown Denver reported 12.2 inches.

What will Denver’s official snow records show? A mere 5.7 inches. This is a direct result of the National Weather Service’s insistence on having Denver’s official measurements taken at Denver International Airport.

Data was collected in downtown Denver from 1872 through December 1948, then at the Stapleton Airport Office from January 1950 through February 1995. In March 1995, the service made the station at DIA the city’s official station for most meteorological observations. In 2008, they began taking official snowfall measurements out there.

Being so far from the Mile High City’s population center, the data collected there is entirely unrepresentative of what residents experience. Further, the move has skewed our climate records rendering comparisons to historical data invalid.  It is highly frustrating and is a significant issue which the National Weather Service dismisses.

Local television meteorologists have long railed against the change in station, most notably Mike Nelson of Denver 7. With this storm, Ashton Altieri of CBS 4 called the National Weather Service out on it.

Climatology, Thornton Weather

February 2024 weather recap: Much warmer and wetter than normal

Thornton, Colorado's February 2024 temperature Summary. (ThorntonWeather.com)
Thornton, Colorado’s February 2024 temperature Summary. (ThorntonWeather.com)

The past month was one that started out with some excitement in the form of snow (after rain) but then became far calmer and warmer.

On the third of the month, we saw a system move in that initially offered precipitation in the form of rain, and a good bit of it. That eventually transitioned to snow giving us 3.2 inches. Our biggest snowfall of the month of 4.2 inches followed on the 10th. We then saw a few other, smaller snowfalls, enough to put the month above average in terms of snowfall and precipitation.

Temperatures never really got all that cold. There was only one single digit reading for the month, less than you would expect and, particularly toward the latter part of the month, spring-like mercury readings were pretty common.

Thornton’s average temperature for the month came in at 38.5 degrees. That was far above our 18 year running average for February of 31.8 degrees. That put February 2024 into the books in a tie with February 2016 for the second warmest February. Number one is February 2017 at 40.1.

Out at Denver International Airport where the Mile High City’s official measurements are taken, the month saw an average temperature of 37.6 degrees. That too was well above their long term average for February of 32.7 degrees.

Temperatures in Thornton ranged from a high of 68.6 degrees on the 20th down to a low of 8.9 degrees on the 17th. Denver twice saw its warmest reading of 65 degrees and its coldest reading was 7 degrees.

Precipitation was bountiful, not only due to some decent snow but mainly due to the rain on the third. Thornton saw 1.67 inches of liquid precipitation for the month, a full inch above the 18 year February average of 0.67 inches.

Denver was drier, but not by a lot. The airport recorded 1.46 inches of liquid precipitation. This versus the Mile High City’s long term February average of 0.41 inches.

In terms of snowfall, we lacked any big storms but the littler ones added up. Thornton recorded 11.8 inches of the white stuff, just above the 18 year running average of 11.6 inches.

Denver bested us on the snowfall front recording 13.7 inches, well above their long term February average of 5.7 inches.

Click here to view Thornton’s complete February 2024 climate summary report.

Thornton, Colorado's February 2024 precipitation Summary. (ThorntonWeather.com)
Thornton, Colorado’s February 2024 precipitation Summary. (ThorntonWeather.com)
Climatology, Thornton Weather

Thornton’s February 2024 weather preview: Temps begin to warm, snow can be elusive

February in Colorado typically brings to an end an extended period when average temperatures are at their lowest. Winter begins to loosen its grip and temperatures get warmer but precipitation is not a particularly common event during the month.

Thus far, our snow season has been a bit of a disappointment and while January brought some of the what stuff, it wasn’t a lot. February is only our sixth snowiest month so we can’t count on much else.

Temperatures however do usually see a nice rebound during the month. Average high temperatures climb from an average of 44 degrees at the start to 50 degrees by the end of February.

For the complete February preview including a look at historical averages and extremes as well as a look at what long range forecasts are predicting, click here. 

Climatology, Thornton Weather

January 2024 weather recap: Some extreme cold, some very pleasant weather

Thornton, Colorado's January 2024 temperature summary. (ThorntonWeather.com)
Thornton, Colorado’s January 2024 temperature summary. (ThorntonWeather.com)

The month of January offered a bit of a mixed bag of weather, showcasing the kinds of extremes our weather is known for. While we saw a period of bitter cold, the month ended with a string of mild days.

The first few days of the month were nice enough, with calm, dry conditions and temperatures above normal. From there, we entered a period dominated by colder than normal mercury readings. Most notable, Arctic air that arrived on the 12th and sent the thermometer down.

The following three days saw highs only in the single digits and four mornings with below zero lows. During that period we also received our most notable snowfalls of the month although they did not amount to much. Thornton received 1.8 inches on the 13th and 2.5 inches on the 15th.

The last half of the month saw things turn warmer with above normal readings for the final 10 days of the month. The last four days were very nice with readings of 60+ degrees.

In the end, Thornton’s January 2024 average temperature came in at 28.7 degrees. That was 1.9 degrees below our running 18-year average for January of 30.6 degrees. Temperatures ranged from a high of 62.5 degrees on the 28th down to a low of -12.2 degrees on the 16th.

Out at Denver International Airport where the Mile High City’s official measurements are taken, they saw an average temperature for the month of 28.2 degrees. This was well below their long term January average of 31.7 degrees.

January is rarely a wet month and it was not in 2024. Thornton saw a mere 0.25 inches of snowmelt. This was a good bit below our January average of 0.42 inches.

Denver received more precipitation than us, but not by much. They saw 0.28 inches in their bucket, a good bit below their January average of 0.38 inches.

Snowfall for the month was respectable but as indicated above, dry. Thornton had a January total of 5.4 inches. This was 0.9 inches below our 18-year average for January of 6.3 inches.

Out at the airport, Denver saw less than us recording only 3.6 inches. This was well below the Mile High City’s January average of 6.4 inches.

Click here to view Thornton’s complete January 2024 climate summary report.

Thornton, Colorado's January 2024 precipitation summary. (ThorntonWeather.com)
Thornton, Colorado’s January 2024 precipitation summary. (ThorntonWeather.com)
Climatology, Thornton Weather

Thornton’s 2023 weather recap: Not a lot of drama but a big dose of precipitation

Thornton, Colorado 2023 Temperature Summary (ThorntonWeather.com)
Thornton, Colorado 2023 Temperature Summary (ThorntonWeather.com)

That’s another year in the books and looking back, there really weren’t any particularly notable events in terms of the weather for Thornton. We did end up a bit warmer than average and precipitation was well above normal.

The year started off on the cold and snowy side. January saw temps more than 3 degrees cooler than average and it was our snowiest month of the calendar year with 11.2 inches. The next few months were relatively quiet. After three consecutive months with below normal levels of precipitation, May arrived and Mother Nature let it rain.  Thornton recorded almost double the May average.

June was cooler than normal and rain continued to arrive in copious amounts with us getting more than double the average. July continued to be wetter than normal and temperatures climbed with Thornton hitting or beating the 100 degree mark three times. August saw a bit warmer than average temperatures and again saw three days with 100 degree or warmer readings.

As temperatures cooled, we continued to run warmer than average. In fact, the last six months of 2023 saw warmer than average temperatures. Most notably, December was a whopping 6.6 degrees warmer than average. The last three months of the year also saw below average precipitation.

In the end, Thornton saw an average annual temperature of 51.3 degrees. This was a bit above the running 17-year annual average of 50.7 degrees.

Out at Denver International Airport where the Mile High City’s official records are taken, they were just a hair cooler with an annual average of 51.0 degrees, 0.2 degrees below Denver’s long term annual average.

Precipitation was most notable for the year as Thornton saw 21.89 inches of rain and snow melt. That put the year in the books as the wettest year of the past 17 years and easily bested the annual average of 15.30 inches.

Denver was quite wet as well, although not quite as much so as us. They recorded 18.94 inches in their bucket, 4.46 inches above their annual average.

Click here to view Thornton’s 2023 climate report.

Thornton, Colorado 2023 Precipitation Summary (ThorntonWeather.com)
Thornton, Colorado 2023 Precipitation Summary (ThorntonWeather.com)
Climatology, Thornton Weather

December 2023 weather recap: Mild, dry weather continues

Thornton, Colorado December 2023 Temperature Summary (ThorntonWeather.com)
Thornton, Colorado December 2023 Temperature Summary (ThorntonWeather.com)

Thornton wrapped up 2023 with similar weather conditions as had been seen the previous two months. Temperatures were well above normal and precipitation was scarce.

The month was a quiet one, lacking any sort of real weather drama. We started out on the cool side but then put together a string of well above normal days from the 4th to the 7th. We then turned colder and saw our first and biggest snow of the month, 1.7 inches, on the 9th. The balance of the month saw some ups and downs, mainly ups, with only three more snowfalls, all very light.

Thornton ended the month with an average temperature of 37.1 degrees. This was far above the running 17-year average for the month of 30.5 degrees. It also put December 2023 into the books as the warmest December of those 17 years, besting the previous warmest of 37.0 degrees in 2021.

The warmest temperature of 68 degrees was seen on the 19th while the coldest temperature of 11.2 degrees came on Christmas morning.

As measured at Denver International Airport, the Mile High City was similarly warm. Denver’s December 2023 average temperature was 37.4 degrees, besting Thornton’s number. That too was well above their long-term average for the month of 31.2 degrees and goes into the Denver weather history books tying December 1929 as the 17th warmest December on record.

Along with the warmth, we saw little precipitation. Thornton recorded a mere 0.26 inches in the bucket. That was only about half of the 17-year running average for December of 0.45 inches. Much of that can be attributed to the relative lack of snowfall as we only saw 3.1 inches of the white stuff. That is less than half of the 8.4 inches Thornton has averaged during December over the past 17 years and the third least snowy December over that period.

Out at the airport, it was quite dry as well. Denver recorded only 0.12 inches in their bucket, far below the long-term average of 0.35 inches. The Mile High City was also lighter on snow than us, seeing only 1.4 inches. That puts December 2023 into the books as the 18th least snowy December on record.

Click here to view Thornton’s complete December 2023 climate summary report.

Thornton, Colorado December 2023 Precipitation Summary (ThorntonWeather.com)
Thornton, Colorado December 2023 Precipitation Summary (ThorntonWeather.com)
Climatology, Thornton Weather

Astronomical winter arrives Thursday, offers up the shortest day of the year

The Winter Solstice
Winter officially begins at 8:27pm MST on Thursday, December 21, 2023.

Astronomical winter arrives in Thornton Thursday evening and with the solstice also comes the shortest day of the year.

Winter officially begins at 8:27pm MST on Thursday, December 21, 2023.

The Winter Solstice occurs when the North Pole is tilted at its furthest from the sun – 23.5 degrees away. This results in the shortest day of the year in the Northern Hemisphere.

Here in Denver, with sunrise at 7:17am and sunset at 4:38pm, our day Saturday will be 9 hours, 21 minutes and 14 seconds long.

The following day, Friday, it will be about a second longer and each day from now through to the Summer Solstice in June will get gradually longer as well.

While we have a short day on the solstice, it is nothing like what will be experienced in the Arctic Circle.  Areas north of there to the North Pole will have no direct sunlight at all.  Conversely, areas south of the Antarctic Circle toward the South Pole will have 24 hours of daylight and have a midnight sun.

Did you know that there is a difference between the astronomical seasons that we are discussing here and meteorological seasons?

Meteorological seasons differ slightly and are geared toward matching the calendar with the annual temperature cycle. This is done primarily for meteorological observing and forecasting and in many ways it is more logical than the astronomical seasons.

For the Northern Hemisphere, the meteorological spring covers the months of March, April and May. Summer brings the hottest months of the year and so meteorological summer is June, July and August. Meteorological fall then is September, October and November followed by the coldest months of December, January and February as meteorological winter.

Climatology, Thornton Weather

November 2023 weather recap: Thornton gets another mild, dry month

Thornton, Colorado's November 2023 Temperature Summary. (ThorntonWeather.com)
Thornton, Colorado’s November 2023 Temperature Summary. (ThorntonWeather.com)

For the second month in the row, Thornton saw a period of temperatures above normal and precipitation below normal. Were it not for a cold snap and snow to end the month, it would have been much worse.

Most of November saw a continuation of the mild, dry weather we saw in October. For the first three weeks, temperatures were largely above normal and precipitation was virtually non-existent. In fact, 19 out of the first 22 days of the month saw mercury readings above normal and a mere 0.02 inches had been recorded in the rain bucket and we had no snow.

Mother Nature finally changed course and chilled us out and brought our first snow of the month during the last week. We saw a few days with well below normal temperatures and 4.3 inches of snowfall were recorded over a two-day period.

Thornton’s average temperature for November 2023 came in at 42.2 degrees. This was well above our 17-year running average for November of 39.7 degrees. Temperatures ranged from a high of 79.8 degrees on the 5th down to a low of 11.7 degrees on the 26th.

Out at DIA where the Mile High City’s official measurements are taken, it was similarly warm. Denver had an overage temperature for the month of 43.2 degrees, again, well above their average of 39.4 degrees.

In terms of precipitation, Thornton saw a mere 0.20 inches of liquid precipitation during the month. This was less than half of the 0.47 inches running November average and tied for the third driest November of the past 17 years.

Denver recorded 0.18 inches out at the airport. Far below their long term November average of 0.64 inches.

Snow was below normal both here in Thornton and at DIA. Thornton recorded 4.3 inches, a good bit below the 5.7 inch November average of the past 17 years. Denver saw less than us with 2.9 inches, far below their long term November average of 7.3 inches.

Click here to view Thornton’s complete November 2023 climate summary report.

Thornton, Colorado's November 2023 Precipitation Summary. (ThorntonWeather.com)
Thornton, Colorado’s November 2023 Precipitation Summary. (ThorntonWeather.com)