From NWS
1985: Rain fell across all of Iowa on September 29-30 and into the morning of October 1st across the north. Unseasonably cold temperatures resulted in snow and sleet mixing with the rain at times in some areas, although most of this melted as it fell due to warm ground temperatures. At Des Moines a trace of snow was recorded on both the 29th and 30th, making this one of only two years (along with 1942) that snow has ever been recorded at Des Moines in the month of September. Elsewhere Audubon and Storm Lake each reported a half inch of snow from this system although it melted quickly as precipitation changed back to rain.

1899: Unseasonably cold weather settled across Iowa on the last five days of September. On the 26th-28th many locations around the state reported frost with a few stations recording freezes on each day. On the morning of the 29th temperatures fell even further, all the way down to 15 F at Sheldon and Sibley which established the all-time Iowa September record that would be tied just the next day. Other low temperatures on the 29th included 17 F at Atlantic and Primghar, 18 F at Denison, 19 F at Carroll and Logan, and 20 F at Forest City, Harlan, and Rockwell City.

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