Precipitation: The statewide average precipitation for April in Illinois was 7.01 inches, 3.23 inches above normal and the 2nd wettest April on record. Here are the top five wettest Aprils. Notice a pattern? Three out of the five have been since 2011.
- April 2011 – 7.62 inches
- April 2017 – 7.01 inches
- April 1957 – 6.99 inches
- April 2013 – 6.93 inches
- April 1927 – 6.87 inches
The largest monthly total for April in Illinois was Carbondale with 14.41 inches. Several other sites in southern Illinois had similar amounts including Bush (Williamson County) with 13.63 inches, West Frankfort (Franklin County) with 13.35 inches, Kaskaskia (Randolph County) with 13.34 inches, and Murphysboro (Jackson County) with 13.02 inches.
Temperature: The statewide average temperature for April was 56.4 degrees, 3.8 degrees above average and the 11th warmest April on record. The warmest reading for April was 89 degrees at Kaskaskia on April 20. The coldest reading for the month was 19 degrees at Morrison on April 10.
Statewide records of temperature and precipitation go back to 1895.
Here are the temperature departures for 2017. As you can see, every month in 2017 has been well above normal. So far this January-April is the 2nd warmest such period on record with a statewide average temperature of 43.2 degrees, 5.4 degrees above normal. Only 2012 was warmer at 44.5 degrees, 6.7 degrees above normal. [corrected from an earlier version]