Illinois State Water Survey Illinois State Climatologist

An Extremely Warm September has us Wondering, Where is Fall?

The statewide average September temperature was 73.0 degrees, 6.2 degrees above the 1991-2020 average, 6.8 degrees above the 20th century average, and 5.5 degrees above the most recent 30-year average. It was the warmest September on record in Illinois. The statewide total September precipitation was 3.01 inches, 0.34 inches below the 1991-2020 average, 0.49 inches […]

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Mild October Had a Chilly End

The preliminary statewide average October temperature was 56.7 degrees, 1.9 degrees above the 1991–2020 average and tied for the 31st warmest on record going back to 1895. The preliminary statewide total October precipitation was 3.46 inches, 0.20 inches above the 1991–2020 average and the 41st wettest on record. Data are provisional and may change slightly […]

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October Brought Real Fall to Illinois

The preliminary statewide average October temperature was 53.1 degrees, 1.6 degrees below the 1991–2020 average and tied for the 40th coolest on record going back to 1895. The preliminary statewide average total October precipitation was 2.30 inches, 0.61 inches below the 1991–2020 average and tied for 52nd driest on record statewide.     Data are provisional […]

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