Looking at the preliminary numbers, Illinois has experienced its warmest, and second wettest December on record. Statewide records go back to 1895.
Precipitation: the statewide average precipitation was 6.70 inches, 4.01 inches above average and the second wettest December on record.
The wettest December on record was in 1982 with 7.17 inches. Like this year, that was also during a major El Niño event.
Temperature: the statewide average temperature for December is 40.6 degrees, an incredible 10.7 degrees above average and the warmest December on record. This December beat the old record by 1.7 degrees that was set in 1923 with 38.9 degrees.
[this posted was updated on January 2, 2016, to reflect the latest information for December 2015]