CHAMPAIGN, Ill. – Based on preliminary data in Illinois, the statewide average precipitation for 2009 was 50.3 inches, 11 inches above normal. This was the fourth wettest year on record for the state based on data going back to 1895, according to State Climatologist Jim Angel of the Illinois State Water Survey (http://www.isws.illinois.edu).
The wettest year on record was 1993 with 51.2 inches, followed closely by 2008 with 50.5 inches, and 1990 with 50.4 inches. All four wettest years have been in the last 20 years of the record. The normal statewide annual precipitation in Illinois is 39.2 inches.
The statewide precipitation for December was 4.1 inches, 1.4 inches above normal. While much of that fell as rain, areas north of Interstate 64 reported measureable snow totals. Significant snow was reported north of Interstate 80 with totals of 8 to 21 inches.
The statewide average temperature for December was 28.9 degrees, 1.0 degree below normal. As a result, the annual temperature for 2009 was 51.2 degrees, 0.8 degrees below normal. The outstanding colder-than-normal months in 2009 were January, July, August, and October. January was 4.2 degrees below normal, July was 5.2 degrees below normal, August was 2.6 degrees below normal, and October was 4.4 degrees below normal.
"So the cold, wet December finishes out a cold, wet year in Illinois. The outstanding feature is the two back-to-back exceptionally wet years. Together they account for 100.8 inches of precipitation. That is an extra 22.4 inches of precipitation over the two-year period," concludes Angel.
The Illinois State Water Survey at the University of Illinois at Urbana-Champaign under the Institute of Natural Resource Sustainability is the primary agency in Illinois concerned with water and atmospheric resources.
