The statewide average temperature for October in Illinois was 59.8 degrees, 5.4 degrees above normal and the 7th warmest October on record.
The statewide average precipitation for October in Illinois was 2.38 inches, 0.86 inches below normal. There were a few bands of 3 to 5 inches across northern Illinois and along the Interstate 70 corridor (left panel). Outside of those areas, October was drier than normal (right panel). The site with the largest monthly rainfall total was Palos Park, in Cook County, with 5.51 inches (IL-CK-50).
Year to Date
Illinois has experienced above-normal temperatures in 9 out of the 10 months in 2016 (see graph below). As a result, this is the 4th warmest January through October on record for Illinois at 58.0 degrees and 2.5 degrees above normal. Here are the top five warmest years in Illinois:
- 2012 with 59.1 degrees
- 1921 with 58.7 degrees
- 1998 with 58.2 degrees
- 2016 with 58.0 degrees
- 1938 with 57.6 degrees
The statewide average precipitation for 2016 so far is 35.65 inches, 1.85 inches above normal. Other than the record wet July-August, 2016 would have been drier than normal.
Here are the monthly departures for 2016 (click to enlarge).
Note: the statewide records go back to 1895. These are preliminary numbers with final numbers arriving in the next week.