Illinois State Water Survey Illinois State Climatologist

Warm, Dry December Concludes a Cold, Wet Year

December temperatures were well above the long-term average across the state, breaking dozens of local daily maximum and minimum temperature records. The preliminary statewide December average temperature was 35.2 degrees, about 5 degrees above the 1981-2010 normal and the 18th warmest on record. Preliminary data show December was drier than average for most of the […]

Read More from Warm, Dry December Concludes a Cold, Wet Year

Second Coldest April on Record in Illinois

Temperature Based on the official data, the statewide average temperature was  44.5 degrees,  8.1 degrees below normal. It was the second coldest April on record, only beaten by 43.1 degrees set in April 1907. Our statewide records go back to 1895. Normal refers to a specific benchmark, the 1981-2010 average. See the longer explanation here. Here are […]

Read More from Second Coldest April on Record in Illinois

5th Warmest November, 2nd Warmest Fall in Illinois

Temperature This was the 5th warmest November on record for Illinois, based on preliminary data. The statewide average temperature was 47.4 degrees, and 4.9 degrees above normal. Here are the top ten warmest Novembers in Illinois since 1895: 2001 with 49.9°F 1931 with 49.1°F 1909 with 48.8°F 1999 with 48.4°F 2016 with 47.4°F  2009 with […]

Read More from 5th Warmest November, 2nd Warmest Fall in Illinois

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 […]

Read More from Average Date of First Snow in Illinois