Illinois State Water Survey Illinois State Climatologist

2025 Was Warm and Dry in Illinois

Illinois was both warmer and wetter than the 1991–2020 normal in 2025. The statewide average annual temperature was 53.6 degrees, 1.0 degree above normal and the 18th warmest year on record statewide. Statewide average total precipitation in 2025 was 32.94 inches, 7.8 inches below normal and the 23rd driest year on record statewide. Another Very […]

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Fall Ended and Winter Really Began in November

The preliminary statewide average November temperature was 43.6 degrees, 1.4 degrees above the 1991-2020 average and the 32nd warmest November on record. The preliminary statewide average total November precipitation was 2.14 inches, 0.94 inches below the 1991-2020 average and the 45th driest on record statewide. Data are provisional and may change slightly over time. Mild […]

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Fall Begins with a Warm and Very Dry September

The preliminary statewide average September temperature was 68.8 degrees, 2.0 degrees above the 1991–2020 average and tied for the 27th warmest on record going back to 1895. The preliminary statewide total September precipitation was 2.60 inches, 0.75 inches below the 1991–2020 average and the 41st driest on record. Data are provisional and may change slightly […]

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Mild May Wraps Up an Otherwise Warm Spring in Illinois

The preliminary statewide average May temperature was 63.0 degrees, 0.2 degrees below the 1991–2020 average and the 58th warmest on record going back to 1895. The preliminary statewide average total May precipitation was 3.75 inches, 1.02 inches below the 1991–2020 average and the 55th driest on record statewide.     Data are provisional and may change […]

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