Northeastern Illinois

Included Counties: 
Boone, McHenry, Lake, DeKalb, Kane, DuPage, Cook, La Salle, Kendall, Grundy, Will
Watersheds: 
Chicago, Des Plaines, Green, Kankakee, Kishwaukee, Lake Michigan, Little Calumet-Galien, Lower Fox, Lower Illinois-Senachwine Lake, Lower Rock, Pike-Root, Upper Fox, Upper Illinois, Upper Rock, Vermilion

Geography

Illinois Climatic Division 2 is bounded to the northeast by the southern tip of Lake Michigan. It includes the Greater Chicago area and stretches into the agricultural heartland to the south and west. Moving away from Lake Michigan and the Chicago area, the terrain is increasingly dedicated to agriculture.

Overview

The northern areas of the Northeastern Climatic Division of Illinois can see strong lake effect from Lake Michigan, while the southern areas are characteristically more continental. Near Chicago, Lake Michigan moderates temperatures year-round, and can generate intense lake-effect snowfall during periods of northwesterly and westerly wind. Farther inland and overall, large daily variations in temperature are more common than in climatic divisions nearer the Great Lakes. But as with the surrounding region, the division does not usually experience prolonged periods of extreme heat and humidity in the summer or prolonged, extreme cold during the winter. Summers are generally hot and humid, and winters, while not as severe as in more northern locations, can be cold with moderate to heavy snowfall.
 

Changes In Precipitation

 in.cm.%
Annual3.99.911.22
Winter0.61.612.76
Spring0.61.56.03
Summer0.71.96.31
Fall1.64.220.49

Linear best-fit changes are calculated over the period 1950-2012. Percentage changes are calculated relative to the 1951-1980 historical reference period.

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Changes In Temperature

 °F°C
Annual2.31.3
Winter2.71.5
Spring3.41.9
Summer1.40.8
Fall1.40.8

Linear best-fit changes are calculated over the period 1950-2012. Percentage changes are calculated relative to the 1951-1980 historical reference period.

Seasonal Precipitation

Seasonal Temperature