October Trick or Treat

Pat Guinan
State Climatologist
Commercial Agriculture/University of Missouri Extension

For many Missourians autumn is their favorite season and October is their favorite month. Cool, crisp mornings transition to sunny, mild afternoons and the trees respond to these temperatures and shorter days in a blaze of color. Ideally, the best ingredients to set the stage for vibrant colors are adequate moisture throughout the growing season followed by drier weather during September and October with cool, but not freezing nights, and abundant sunshine.

Even though fall colors are a guarantee for October in Missouri, Mother Nature doesn't always cooperate with the "chamber of commerce" weather conditions we anticipate for the month. Historical climate records for Missouri reveal years when Mother Nature turned October into trick rather than a treat.

Our hottest Halloween occurred on October 31, 1950 when most locations across Missouri reported high temperatures in the upper 80's and lower 90's. Brunswick, Lexington and Elsberry, MO all reported a maximum temperature of 91° which was the highest in the state. Alternatively, Missouri's coldest Halloween morning occurred on October 31, 1925 when bone chilling temperatures plummeted into the teens and lower 20's statewide. A few locations tumbled further, into the single digits, with the lowest temperature of 6°F reported in Chillicothe, MO.

Additionally, 1925 has the distinction of being the coldest October on record for Missouri. According to a Weather Bureau summary for October 1925, the adjective used to describe the month in Missouri was "horrid". The summary went on to state "The first three days were quite balmy but nearly every day thereafter was colder than normal, some as much as 20 to 25 degrees colder. Freezing temperatures occurred nightly after the 19th and a cold wave with snow swept the state the night of the 27th, followed by winter cold; for 40-75 consecutive hours, the temperature did not rise above freezing".

October also has the dubious distinction of being the earliest month to witness snowstorms. More recently, a major snow event occurred on October 22-23, 1996 when portions of northwestern and west central Missouri reported 3-9 inches of snow. Heavy wet snow fell on trees that were in leaf leading to numerous downed branches and power lines. The Kansas City area reported 130,000 residences without power and $1.5 million in property damage due to the storm.

On the other extreme, triple digit temperatures have been experienced in Missouri during October but the occurrence is very rare. Since 1890, there have only been 2 documented days when the mercury reached the century mark in Missouri. The two dates and locations to reach 100°F are October 13, 1899 in Appleton City and October 7, 1939 in Edgerton, MO.