After a warm first few days of September, cooler weather became more dominant through the middle of the month and beyond, with more consistent below-normal temperatures and a few days in which average temperatures were as much as 10 to 20 degrees below normal.
During this cool period, an earlier-than-normal first frost of the season occurred in a large part of the state at the end of the second week of September. A few locations in the state had official low temperatures drop to 32 or slightly lower, well ahead of the normal first 32-degree reading.
Later in the month, average temperatures were running below normal with greatest departures generally in some eastern areas of the state.
Parts of Iowa also continued to receive some fairly heavy rainfall during the first half of September, with some...