Denver Climatological Preview - May 2023

Preview of Denver's May Weather - The One Constant - Change!

Colorado natives and those that have lived here long enough know that Denver and Colorado weather changes considerably throughout the year. The month of May almost seems to pack four seasons of weather conditions into 31 days. You name it, it can happen.

This being the latter half of spring, May does mean warm temperatures. Temperatures in the 80’s are common and reaching into the 90’s is not unheard of. The normal highs start out at 66 on the first but by the end of the month that climbs to 77. The record high for the month was recorded on May 26, 1942 of 95 degrees.

While that warmth may sound inviting, we usually aren’t done with the cold just yet. The average day of the last freeze is May 5th but the latest date is June 8th so it can remain cold at night. In fact, the record low for May was on the 3rd of the month in 1907 when Denver got down to 19 degrees.

To further drive that point home, the record low temperature for each day of May is at or below the freezing mark except on two days (the 27th and 31st). Don’t get too discouraged though as the normal low is 38 on the 1st of the month and it climbs throughout the month to a normal low of 48 degrees on the 31st.

Snow can and does fall in May with an average of 1.1 inches of the white stuff coming down in Denver based on the 1981 - 2010 average (1.7 inches all time May average). However, the onset of warmer temperatures coupled with Denver's high elevation intensifies late season cold air masses and on the average May snow occurs in about two out of every five years.

Many years see little or no snow in May. In fact, 14 of the past 30 Mays saw no snow and 8 saw only a trace. May's average numbers are skewed a bit by three years in that range, 2003, 2001 and 1983, when more than 7 inches was measured. In short it can be an all or nothing situation with snow in May.

One notable May in the recent past was in 2003 when snow started falling on the 9th of the month and continued overnight before stopping with 7 inches on the ground in Denver. That particular storm caused tremendous amounts of damage to area trees as it was a typical spring storm and very wet. Most trees had opened up and had all their leaves out and even thick branches snapped under the weight of the snow.

The year of 1898 holds the record when 15.5 inches of snow fell during May that year.

Severe weather season normally gets started in earnest in May with violent thunderstorms and large hail and tornadoes a possibility. Moisture spinning up from the Gulf of Mexico into the state collides with cold air from Canada or the Pacific Northwest making conditions ripe for these types of events. Remember that it was on May 22nd of 2009 that the Windsor Tornado struck so the danger is very real.

May is the wettest month of the year and on the average precipitation occurs once every three days. An average of 2.12 inches of precipitation falls during the month. For you sun lovers, unfortunately we have to report that May is tied with November as having the lowest percentage of possible sunshine.

May Extremes

May: Denver's Top 5 Coldest (Mean Temperatures):
48.7 Degrees 1917
50.0 Degrees 1995
50.1 Degrees 1935
50.3 Degrees 1907
51.4 Degrees 1983

May: Denver's Top 5 Warmest (Mean Temperatures):
64.7 Degrees 1934
63.2 Degrees 1994
62.0 Degrees 1886
61.7 Degrees 1958
61.6 Degrees 1879, 1974

May: Denver's Snowiest
15.5 Inches 1898
13.7 Inches 1950
13.5 Inches 1978
13.2 Inches 1912
12.0 Inches 1917

May: Denver's Least Snowy
Numerous years with no snowfall (42).

May: Denver's Wettest
8.57 Inches 1876
7.31 Inches 1957
6.12 Inches 1969
5.06 Inches 1973
4.95 Inches 1935

May: Denver's Driest
0.06 Inches 1974
0.09 Inches 1886
0.15 Inches 1899
0.22 Inches 1919
0.34 Inches 1966, 1977

May 2021 Outlook

Long range outlooks from the Climate Prediction Center point to a potentially dry month of May. The agency gives the northern half of Colorado equal chances of seeing below, above or near normal temperatures. However, for precipitation, it gives above average chances of the Front Range seeing below normal levels.

For More Information

Temperature Normals and Extremes for May

Monthly Temperature, Rainfall and Snowfall Extremes for May

MAY AVERAGE STATISTICS * Normals & Means, 1981 - 2010

TEMPERATURE
AVERAGE HIGH	71.5
AVERAGE LOW	42.7
MONTHLY MEAN	57.1
DAYS WITH HIGH 90 OR ABOVE	0.6
DAYS WITH HIGH 32 OR BELOW	0
DAYS WITH LOW 32 OR BELOW	2
DAYS WITH LOWS ZERO OR BELOW	0

PRECIPITATION
MONTHLY MEAN	2.12 INCHES
DAYS WITH MEASURABLE PRECIPITATION	9
AVERAGE SNOWFALL	1.1 INCHES
DAYS WITH 1.0 INCH OR MORE SNOWFALL	0 (* Less than one)

MISCELLANEOUS MAY AVERAGES
HEATING DEGREE DAYS	265
COOLING DEGREES DAYS	21
WIND SPEED (MPH)	9.3 MPH
WIND DIRECTION	SOUTH
DAYS WITH THUNDERSTORMS	6.4
DAYS WITH DENSE FOG	0.5
PERCENT OF SUNSHINE POSSIBLE	64

MAY EXTREMES
RECORD HIGH	95 ON 5/26/1942
RECORD LOW	19 ON 5/3/1907
WARMEST	64.6 IN 1934
COLDEST	48.7 IN 1917
WETTEST	8.57 INCHES IN 1876 (Wettest month in Denver history)
MAXIMUM 24 HOUR MOISTURE	6.53 INCHES IN 1876 (Most in Denver history)
DRIEST	0.06 INCH IN 1974
SNOWIEST	15.5 INCHES IN 1898
MAXIMUM 24 HOUR SNOWFALL	10.7 INCHES IN 1950
LEAST SNOWIEST	0.0 INCH (41 YEARS WITH ZERO SNOWFALL)

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