September Weather

September wrapped up as a very warm, dry month for Iowa, an about-face from the month before.

State climatologist Harry Hillaker says during the last week in the month, Iowans endured temperatures much warmer than normal, well into the 90s in many areas. “The month started out rather on the cooler side. The first seven or eight days, temperatures were well below normal,” Hillaker says. “The rest of the month, with a few small exceptions, was very much on the warmer side. The month as a whole ended up being about 4 degrees above normal for temperatures.”

It ended up being the 11th warmest September in Iowa out of 145 years of record-keeping. Coincidentally, the prior month was the 12th coolest August in Iowa on record. The hottest day of September fell on the 23rd when Iowa City reported 95 degrees, while the coldest report was 35 degrees, both on September 7th in Stanley and on September 30th in Cresco. The highest temperature in Storm Lake in September was 90 on the 23rd… and the coolest, 45 on the 7th.

Rainfall during September was widely varied across Iowa. “A very dry first half of the month, very little rain anywhere in the state the first half of September,” Hillaker says, “but the rainfall became much more common in the second half of the month, though most areas ended up well below normal.” Storm Lake received 1.61 inches of rain in September.