
You didn’t need a thermometer to know that June 2012 was extraordinarily hot. What is normally one of the most pleasant months in Thornton turned into a scorcher with high temperature records seemingly falling daily.
The first half of the month was unseasonably warm but that was only a warm-up (pun intended) for what would come during the latter half of the month.
Officially for Denver nine daily high temperature records were tied or broken. The first record fell on June 4th and then the records on the 9th, 17th, 18th, 22nd, 23rd, 24th, 25th and 26th followed suit.
The temperature at Denver International Airport hit 100 degrees or higher six times during the month – the most ever recorded in June. Five of those 100 degree days were consecutive from the 22nd to the 26th and all of those dates set records. On 17 of the 30 days of the month the temperature reached 90 degrees or higher.
In the end Denver saw an average monthly temperature of 75.0 degrees. This was an astonishing 7.6 degrees above normal and puts June 2012 in the books as the hottest on record.
Thornton, while not quite as warm as DIA, still saw an extraordinarily hot month. We recorded 16 days of 90 degree or higher temperatures, one shy of Denver.
From the time ThorntonWeather.com was founded in October 2006 until the start of June 2012, we had only twice before recorded temperatures of 100 degrees or higher. We doubled that tally in June alone as on four days we reached 100 degrees or higher.

Thornton recorded an average monthly temperature of 73.9 degrees. This was 6.7 degrees above the average of the previous five Junes.
In terms of precipitation, Denver officially recorded 1.22 inches of precipitation which was 0.76 inches below normal. All of that was recorded on the 6th and 7th when thunderstorms rolled through the airport area.
Here in Thornton we didn’t benefit from the thunderstorms nearly as well. A mere 0.11 inch of precipitation fell into our rain bucket, far below the 1.44 average of the past six years.
Thornton’s June 2012 Climate Summary
From the National Weather Service:
CLIMATE REPORT
NATIONAL WEATHER SERVICE BOULDER, CO
649 AM MDT SUN JUL 1 2012
…JUNE 2012…HOTTEST JUNE ON RECORD…
June 2012 was the hottest June in Denver since weather records began back in 1872. The month got off to a warm start with above normal temperatures during the first 9 days of the month. Record maximum temperatures were set and tied on the 4th and 9th respectively. An upper level trough of low pressure which moved across the northern and central Rockies brought cooler temperatures to the region… Resulting in below normal temperatures on the 10th and 11th. Upper level high pressure then reestablished over the region bringing another stretch of above normal temperatures from the 12th through the 19th. Record high temperatures were set both on the 17th and 18th. An upper level trough of low pressure and associated cold front brought some relief to Colorado on the 20th. The high temperature on the 20th was a pleasant 76 degrees…which was eight degrees below normal. Much above normal temperatures returned to Denver the final 10 days of the month as a strong upper ridge of high pressure built over the desert southwest and migrated into the central plains states. A stretch of 5 consecutive 100 degree days occurred from the 22nd through the 26th. This was only the third time in Denver weather history in which this has happened. The other occurrences were July 4th-8th 1989 and July 19th-23rd 2005. In addition…each of the 5 days set new record high temperatures. The 105 degree readings on the 25th and 26th established a new all time record maximum temperature for the month of June and tied Denver’s all time annual record high temperature.
Temperatures:
The average temperature for the month was 75.0 degrees which was 7.6 degrees above normal. This makes June of 2012 the hottest June on record. There were 17 days in which the maximum temperature exceeded 90 degrees. This ties 2002 for the second most 90 degree days in June. June of 2006 still holds the record with nineteen 90 degree days. There were also six days in which the temperature reached the century mark. This is a new record for 100 degree days in the month of June. The old record was 3 days back in June of 1990. The coldest temperature on the month was 43 degrees which occurred on the morning of the 11th. Below is list of temperature records tied or broken during the month.
JUNE 2012 TEMPERATURE RECORDS:
MONTHLY RECORDS:
JUNE 2012 WAS HOTTEST ON RECORD (AVERAGE TEMPERATURE WAS 75.0 DEGREES)
PREVIOUS RECORD WAS JUNE 1994 (AVERAGE TEMPERATURE OF 73.5 DEGREES)
JUNE 22ND-26TH 5 CONSECUTIVE DAYS MAX TEMPERATURE REACHED 100 DEGREES
OTHER OCCURRENCES (JULY 4TH-8TH 1989) (JULY 19TH-23RD 2005)
JUNE 25TH AND 26TH SET ALL TIME JUNE RECORD HIGH TEMPERATURE 105 DEGREES
(PREVIOUS RECORD 104 DEGREES IN 1994)
DAILY RECORDS:
DATE TEMPERATURE TYPE OF RECORD OLD RECORD YEAR(S) SET
JUNE 4TH 94 DEGREES NEW RECORD MAX 93 DEGREES 1946, 1977
1990, 2010
JUNE 9TH 95 DEGREES TIED RECORD MAX 95 DEGREES 1922, 2002
JUNE 17TH 98 DEGREES NEW RECORD MAX 97 DEGREES 2007
JUNE 18TH 100 DEGREES NEW RECORD MAX 99 DEGREES 1936, 1990
JUNE 22ND 102 DEGREES NEW RECORD MAX 98 DEGREES 1874
JUNE 23RD 104 DEGREES NEW RECORD MAX 102 DEGREES 1954
JUNE 24TH 102 DEGREES NEW RECORD MAX 100 DEGREES 2007
JUNE 25TH 105 DEGREES NEW RECORD MAX 100 DEGREES 1991
JUNE 26TH 105 DEGREES NEW RECORD MAX 104 DEGREES 1994
JUNE 26TH 71 DEGREES NEW RECORD HI MIN 68 DEGREES 1936 PREVIOUS YEARS
PRECIPITATION.
PRECIPITATION FOR THE MONTH WAS 1.22 INCHES...WHICH IS 0.76 INCHES
BELOW THE NORMAL 0F 1.98 INCHES. ALL OF THIS PRECIPITATION FELL ON
THE 6TH AND 7TH WHEN STRONG TO SEVERE THUNDERSTORMS MOVED ACROSS
PORTIONS OF THE DENVER METRO AREA. THERE WERE 8 THUNDERSTORMS
OBSERVED AT DENVER INTERNATIONAL AIRPORT DURING THE MONTH. THERE
WERE NO DAYS WITH DENSE FOG WITH A VISIBILITY AT OR BELOW 1/4 MILE
DURING THE MONTH. THE PEAK WIND OF 67 MPH FROM A WESTERLY DIRECTION
OCCURRED ON THE 26TH.
...................................
...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF JUNE 2012...
CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2012
WEATHER OBSERVED NORMAL DEPART LAST YEAR'S
VALUE DATE(S) VALUE FROM VALUE DATE(S)
NORMAL
................................................................
TEMPERATURE (F)
RECORD
HIGH 105 06/26/2012
06/25/2012
LOW 30 06/02/1951
HIGHEST 105R 06/26 104 1 96 06/29
06/25 06/28
LOWEST 43 06/11 30 13 45 06/10
AVG. MAXIMUM 91.7 82.4 9.3 83.3
AVG. MINIMUM 58.4 52.3 6.1 53.0
MEAN 75.0 67.4 7.6 68.2
DAYS MAX >= 90 17 7.9 9.1 7
DAYS MAX <= 32 0 0.0 0.0 0
DAYS MIN <= 32 0 0.0 0.0 0
DAYS MIN <= 0 0 0.0 0.0 0
PRECIPITATION (INCHES)
RECORD
MAXIMUM 4.96 1882
MINIMUM T 1890
TOTALS 1.22 1.98 -0.76 2.43
DAILY AVG. 0.04 0.07 -0.03 0.08
DAYS >= .01 2 8.4 -6.4 8
DAYS >= .10 2 4.6 -2.6 4
DAYS >= .50 2 1.4 0.6 2
DAYS >= 1.00 0 0.3 -0.3 1
GREATEST
24 HR. TOTAL 0.69 06/06 TO 06/07 06/19 TO 06/20
06/30 TO 06/30
06/30 TO 06/30
SNOWFALL (INCHES)
RECORDS
TOTAL 0.4 1919
TOTALS 0.0
DEGREE_DAYS
HEATING TOTAL 6 62 -56 26
SINCE 7/1 5399 6058 -659 5707
COOLING TOTAL 314 133 181 126
SINCE 1/1 365 155 210 135
FREEZE DATES
RECORD
EARLIEST 09/08/1962
LATEST 06/08/2007
EARLIEST 10/07
LATEST 05/05
.................................................
WIND (MPH)
AVERAGE WIND SPEED 12.2
RESULTANT WIND SPEED/DIRECTION 5/169
HIGHEST WIND SPEED/DIRECTION 52/240 DATE 06/02
HIGHEST GUST SPEED/DIRECTION 67/250 DATE 06/02
SKY COVER
POSSIBLE SUNSHINE (PERCENT) MM
AVERAGE SKY COVER 0.50
NUMBER OF DAYS FAIR 8
NUMBER OF DAYS PC 21
NUMBER OF DAYS CLOUDY 1
AVERAGE RH (PERCENT) 33
WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORM 8 MIXED PRECIP 0
HEAVY RAIN 1 RAIN 2
LIGHT RAIN 5 FREEZING RAIN 0
LT FREEZING RAIN 0 HAIL 1
HEAVY SNOW 0 SNOW 0
LIGHT SNOW 0 SLEET 0
FOG 1 FOG W/VIS <= 1/4 MILE 0
HAZE 3
- INDICATES NEGATIVE NUMBERS.
R INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T INDICATES TRACE AMOUNT.