Illinois State Water Survey Illinois State Climatologist

April in Illinois Was Warm, Wet, & Wild

The preliminary statewide average April temperature was 58.8 degrees, 6.2 degrees above the 1991–2020 normal, 7.3 degrees above the 20th Century average, 6.0 degrees above the most recent 30-year average. Last month was the warmest April on record in Illinois. The preliminary statewide total April precipitation was 6.37 inches, 2.13 inches above the 1991–2020 normal, […]

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Average Date of First Snow in Illinois

I have noticed that the average date of the first snow is a popular search term on the blog, so here is the reposting of the median dates of the first measurable snowfall of the season in Illinois. This map is based on 1971-2000 data. While it is not based on the current 1981-2010 averages, the […]

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Illinois – Coolest Place to Live in 2014?

Illinois was one of the coolest places to live in 2014, at least in terms of temperature, according to the recent annual report released by the National Centers for Environmental Information (NCEI). In the map below, the areas in blue show areas where the temperatures were much colder than average for the central US and eastern Canada, […]

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Historical Tornadoes in Illinois and the US

While tornadoes can happen any time of the year, the tornado season really starts to ramp up in March in Illinois (see plot below) and remains active through the spring and on into summer. April, May, and June are the three standout months historically. So far 2015 has been very quiet with no severe weather […]

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