October is a major transition month in Iowa as we say goodbye to the high heat of summer and hello to the cold season. The average high falls 15°, that’s about a degree every two days.
But the difference in extremes is even more stark. Take the record high and record low for example: The hottest temperature ever recorded in Des Moines during October is 95° while the coldest temperature ever recorded in Des Moines during October is 7°. That’s a difference of 88°. Of course it was early in the month when the record high occurred and the end of the month when the record low occurred.
Though the record high is 95°, there have been 11 years since temperature records for Des Moines began in 1878. That’s only 8% of 142 years (and this year does not look to add to it). The 80s are a lot more likely in October. 113 of 142 years have seen highs in the 80s and this weekend looks to confirm that this year will be one too as highs are forecast to reach the lower to middle 80s.
On the flip side, 1925 was the only year to record a low temperature less than 10°, while only 16 years or 11% have experienced lows 20° or lower. A low of 32° and colder is a lot more likely as 92% of years (132 years) on record saw a low at or below freezing.
On average Des Moines sees about 2.64” of liquid precipitation during the month of October; the extremes range from next to no rain all the way to over seven inches of liquid precipitation. The most ever recorded in one day happened on October 7, 1884 when Des Moines saw 3.67” of rain. However, 1884 does not crack the top 5 for wettest Octobers in Des Moines.
Here’s a look at the top 5 wettest and driest Octobers in Des Moines:
Snowfall records for Des Moines began in 1884, so the record consists of 136 years. In that time, 80 of those years (about 59%) experienced an October WITHOUT measurable snowfall in Des Moines. The most recent year without measurable snow in October was 2016. Yes, that means the past four years (2017-2020) have all recorded snowfall in October. In fact, 2020 cracked the top 5 for snowiest Octobers on record in Des Moines.