November 2010 - June 2011 Illinois Divisional Average Temperature Degrees Fahrenheit -99 1901-2000 base period 1901-2000 1101 Illinois CD 1. Northwest 39.8 66 39.8 -0.0 1102 Illinois CD 2. Northeast 40.0 56 40.2 -0.2 1103 Illinois CD 3. West 42.7 48 43.1 -0.4 1104 Illinois CD 4. Central 42.6 58 42.7 -0.1 1105 Illinois CD 5. East 42.2 53 42.4 -0.2 1106 Illinois CD 6. West Southwest 45.4 60 45.3 0.1 1107 Illinois CD 7. East Southeast 45.8 70 45.4 0.4 1108 Illinois CD 8. Southwest 48.6 74 48 0.6 1109 Illinois CD 9. Southeast 48.5 67 48.1 0.4