CEDAR RAPIDS, Iowa (KCRG-TV9) - While warm rain in Iowa can be common in the heart of summer, it doesn’t occur in October.
Of all the heavy rainfall events in October (those with an inch or more of rainfall in a calendar day), 83% of them occur with high temperatures under 70 degrees. One of the biggest reasons for this is not just fighting the calendar, but the way that the bulk of heavy rain occurs in October. These large storm systems usually lay down a warm front in northern Missouri and force the moisture-laden air into the cooler airmass in Iowa. This forces the air to condense into moderate to locally heavy rain.
One of the coolest and wettest days in October records occurred back on Halloween of 1960. The high was 46 degrees and 2.51” of rain fell. What a garbage day that was!