A Preview of Denver's March Weather - Lots of Changes

March in Denver typically means frequent and rapid weather changes. The days grow longer and we start enjoying more sunshine and sometimes summer-like weather. However, on occasion arctic air masses can still force their way south into Colorado dropping temperatures quickly and markedly.

These changes are due to Marches “in between” status – elements during the month have much in common with winter and spring. In addition to arctic fronts, Pacific storms frequently move across Colorado from the west and warm moist air streams up from the Gulf of Mexico northeastward into the state. When these cold fronts collide with the warmer air masses the result can be some crazy weather.

As most locals know, March is the snowiest month of the year. However, thanks to the rapid changes we experience, the snow doesn’t usually stick on the ground for long thanks to lots of sunshine and moderate temperatures. March also usually has the first spring thunderstorms and strong Chinook winds do still make their way on a few days, particularly near the foothills.

Our March weather calendar has many examples of this changeable weather but one of the most notable occurred on March 8, 1992. The morning saw sunny skies and a high temperature of 52 degrees at midday. By the afternoon though, things changed rapidly as tornadoes and thunderstorms with hail developed across the northeast plains, including the Denver Metro area. This was followed by a Canadian cold front that hit in the late afternoon that caused temperatures to drop and blizzard conditions to set in along the Front Range. By the time it was done, 12.4 inches of snow had fallen at Stapleton International Airport and even higher amounts reported across the greater metro area.

More recently, on March 17, 2003 a tornado struck near Bennett when air temperatures were only in the 40’s. Later that day the second strongest winter storm in Denver history began. From March 17th to the 20th 31.8 inches of snow was recorded at Stapleton. A whopping 87.5 inches was recorded near Rollinsville just west of Denver in the foothills. Being a spring storm, this was a very wet storm compared to what we normally receive with an 8 to 1 ratio – i.e. 8 inches of snow yielded 1 inch of moisture. Typically in Colorado we average around a 10 to 1 ratio. March 2003 became the snowiest March in Denver history with 35.2 inches.

However we also have seen dry Marches on occasion including 0.3 inches of snow in 1883, 0.4 inches in 1911 and 1.8 inches in 2004. March 2004 became the second driest March in Denver history recording only 0.14 inches of moisture; the driest was in 1908 when only 0.11 inches was measured.

Severe weather can and does occur in March and you don't have to look any farther than March 28th, 2007 when a tornado ripped through Holly, Colorado. That storm brought Colorado's first tornado casualties since 1960 and serves as a stark reminder that severe weather can hit early in the year. Indeed, as we enter the severe weather season we would remind everyone that tornadoes have been recorded in nine months out of the year in Colorado. Further, statistics show that Adams County actually has the second most tornadoes of any county in the state (next to Weld). Granted most of those occur in the rural eastern portion of the county but it serves to illustrate the fact we live at the western edge of Tornado Alley and need to be aware of the danger.

March 2009 started off very dry as we had only recorded 0.12 inch of precipitation by March 25th and the month was on pace to be the second driest March on record. Mother Nature had other plans and the now infamous March Blizzard of 2009 struck on the 26th. A total of 8.3 inches of snow fell from the event - 7.8 inches on the 26th and 0.5 inch on the 27th as measured at DIA. That snow equated to 0.63 inch precipitation on the 26th and 0.02 inch on the 27th which pushed us a long ways away from the top 10 driest. In fact, the 0.63 inch on the 26th broke the old 24 hour precipitation record of 0.46 inch set in 1899. Thornton recorded a bit more snow and precipitation during that event with 11.4 inches recorded over the two days and 0.68 inch precipitation. 

Looking back at March 2010 –Warmer, drier and snowier than normal

March 2010 was a bit of an unusual one.  Temperatures were warmer than normal and it was drier than average but we received more snow than normal as well.

In terms of temperature, Denver recorded an average temperature of 41.0 degrees which was 1.4 degrees above normal.  The warmest day occurred on the 30th when the mercury climbed to 82 degrees and the coldest was on the 20th when it dropped to 13 degrees.  The 82 degree high on the 30th was a record breaker as it bested the old record of 81 degrees which was set in 1879. 

Thornton's temperatures were very close to those taken at DIA.  We had an average temperature of 40.6 degrees with our warmest day being 81.5 and our coldest 11.6. 

Liquid precipitation for the month was far below normal as 0.80 inch was recorded at DIA.  This was 0.48 inch below the normal of 1.28 inches.  Most of that was recorded in a 24 hour period on the 23rd when 0.61 inch was measured as part of a snowstorm that dropped 10.8 inches of snow.

In terms of snowfall, 12.8 inches was recorded - just above the 11.7 inch normal for March.  This was the third month of the 2009 - 2010 snow season with above normal snowfall.  By the end of the month Denver had recorded 58.8 inches of snow for the season - 7.5 inches above normal for that point of the year. 

Thornton was quite a bit wetter - and snowier - than Denver.  We finished the month with 1.9 inches of precipitation and 15.31 inches of snow. 

Records come with an asterisk: It should be noted that the three records officially recorded for Denver should have an asterisk next to them. The National Weather Service moved the official Denver recording station to DIA in 1995 from its old location at Stapleton. As such, any comparison to years prior to the move in 1995 are not really accurate. For more details on the controversy please visit the related story on the Denver Weather Examiner.

Click here to view the March 2010 Climatology Report.

March 2011 Outlook

For the Denver metro area the Climate Prediction Center 30-day outlook model expects temperatures to be above normal while the precipitation model forecasts slightly below normal precipitation. Refer to the normals below for reference.

For More Information

Temperature Normals and Extremes for March

Monthly Temperature, Rainfall and Snowfall Extremes for March

MARCH AVERAGE STATISTICS * Normals & Means, 1971 - 2000
TEMPERATURE
AVERAGE HIGH	53.7
AVERAGE LOW	25.4
MONTHLY MEAN	39.6
DAYS WITH HIGH 90 OR ABOVE	0
DAYS WITH HIGH 32 OR BELOW	3
DAYS WITH LOW 32 OR BELOW	24
DAYS WITH LOWS ZERO OR BELOW	1
PRECIPITATION
MONTHLY MEAN	1.28 INCHES
DAYS WITH MEASURABLE PRECIPITATION	9
AVERAGE SNOWFALL	11.7 INCHES (1st SNOWIEST MONTH)
DAYS WITH 1.0 INCH OR MORE SNOWFALL	4
MISCELLANEOUS MARCH AVERAGES
HEATING DEGREE DAYS	788
COOLING DEGREES DAYS	0
WIND SPEED (MPH)	9.7
WIND DIRECTION	SOUTH
DAYS WITH THUNDERSTORMS	AVERAGE IS LESS THAN ONE
DAYS WITH DENSE FOG	1
PERCENT OF SUNSHINE POSSIBLE	69
MARCH EXTREMES
RECORD HIGH	84 DEGREES ON 3/26/71
RECORD LOW	-11 DEGREES ON 3/28/1886
WARMEST	50.4 IN 1910
COLDEST	26.4 DEGREES IN 1912
WETTEST	4.56 INCHES IN 1983
MAXIMUM 24 HOUR MOISTURE	2.79 INCHES IN 1983
DRIEST	0.11 INCH IN 1908
SNOWIEST	35.2 INCHES IN 2003
MAXIMUM 24 HOUR SNOWFALL	22.9 INCHES IN 2003
LEAST SNOWIEST	0.3 IN 1970 AND 1883

* Historical weather statistics gathered from the National Weather Service's Denver / Boulder forecast office data archives.