Illinois experienced record or near-record conditions in 2015. Here is the breakdown by category. Overall, Illinois started out 2015 on the cold side but finished with the warmest December on record. However, to me the outstanding feature of 2015 was the wet weather with the wettest June, second wettest December, and sixth wettest year on record.
Temperature:
- The warmest December on record: 40.6 degrees, 10.7 degrees above average.
- The second warmest September – December on record: 53.2 degrees, 4.9 degrees above average.
- The 8th coldest February on record: 19.4 degrees, 11.5 degrees below average.
- Annual: 52.8 degrees, 0.4 degrees above average (not ranked, but of interest)
Precipitation:
- The second wettest December on record: 6.70 inches, 4.01 inches above average.
- The wettest November-December on record: 12.30 inches, 6.15 inches above average.
- The wettest June on record: 9.44 inches, 5.23 inches above average.
- The 6th wettest year on record: 48.49 inches, 8.53 inches above average.
Statewide records go back to 1895.