Illinois State Water Survey Illinois State Climatologist

Dry and Mild Start to Fall

The preliminary statewide average September temperature was 66.8 degrees, 0.6 degrees above the 1991–2020 average and the 57th warmest on record going back to 1895. The preliminary statewide average total September precipitation was 2.66 inches, 0.53 inches below the 1991–2020 average and the 41st driest on record statewide.     Data are provisional and may change […]

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A Cool Start to Fall

September was slightly cooler and wetter than average across Illinois. The preliminary statewide average September temperature was 65.4 degrees, 0.8 degrees below the 30-year normal, and tied for the 45th coolest on record. Preliminary statewide average total precipitation for August was 3.39 inches, 0.16 inches more than the 30-year normal, and the 58th wettest on […]

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Cool, Warm, Wet, Dry, and a Derecho: A Wild August Ends Climatological Summer

August was slightly cooler and much drier than average across Illinois. The preliminary statewide average August temperature was 72.7 degrees, 0.9 degrees below the 30-year normal and the 45th coolest on record. Preliminary statewide average total precipitation for August was 2.01 inches, 1.58 inches below than the 30-year normal and the 15th driest on record. […]

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Cool, Wet May ends Wet Spring

May was much colder and moderately wetter than average across Illinois, bringing an end to a wet climatological spring season. The preliminary statewide average May temperature was 60.5 degrees, 2.2 degrees below the 30-year normal and the 39th coldest on record. Preliminary statewide average total precipitation for May was 5.41 inches, 0.81 inches wetter than […]

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