National Weather Service United States Department of Commerce

Chicago, IL 

Chicago Monthly and Yearly Normals (1991-2020)
  JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
HIGH 31.6 35.7 47.0 59.0 70.5 80.4 84.5 82.5 75.5 62.7 48.4 36.6 59.5
LOW 18.8 21.8 31.0 40.3 50.6 60.8 66.4 65.1 57.1 45.4 34.1 24.4 43.0
AVERAGE 25.2 28.8 39.0 49.7 60.6 70.6 75.4 73.8 66.3 54.0 41.3 30.5 51.3
HEATING DEGREE DAYS 1234 1015 808 468 198 31 2 4 77 355 713 1069 5974
COOLING DEGREE DAYS 0 0 2 8 60 199 326 276 116 15 0 0 1003
PRECIPITATION 1.99 1.97 2.45 3.75 4.49 4.10 3.71 4.25 3.19 3.43 2.42 2.11 37.86
SNOWFALL 11.3 10.7 5.5 1.3 T 0.0 0.0 0.0 0.0 0.2 1.8 7.6 38.4

 

Chicago Mean Number of Days (1991-2020)
Temperatures JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
HIGHS >=90 - - - - 0.8 4.1 6.5 3.7 1.6 - - - 16.7
HIGHS >=50 1.6 3.2 11.5 23.4 30.3 30.0 31.0 31.0 30.0 27.8 12.9 3.4 236.1
HIGHS <=32 16.5 11.2 3.0 0.1 - - - - - - 2.2 10.4 43.4
LOWS <=32 28.1 24.4 19.9 6.0 0.2 - - - 0.1 2.7 14.5 25.4 121.3
LOWS <=0 3.5 1.8 0.2 - - - - - - - - 1.1 6.6

 


Rockford, IL 

Rockford Monthly and Yearly Normals (1991-2020)
  JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
HIGH 29.1 33.4 46.5 59.7 71.2 80.7 83.9 82.0 75.3 62.3 47.1 34.3 58.8
LOW 14.5 17.8 28.1 38.5 49.5 59.6 63.6 61.8 53.5 41.8 30.5 20.2 40.0
AVERAGE 21.8 25.6 37.3 49.1 60.4 70.1 73.8 71.9 64.4 52.0 38.8 27.3 49.4
HEATING DEGREE DAYS 1339 1003 860 482 199 27 3 8 107 412 786 1170 6497
COOLING DEGREE DAYS 0 0 2 5 54 182 274 222 89 11 0 0 838
PRECIPITATION 1.60 1.63 2.40 3.75 4.18 5.23 3.81 4.19 3.62 2.63 2.27 1.93 37.24
SNOWFALL 10.9 8.5 4.9 0.9 T 0.0 0.0 0.0 0.0 0.2 2.3 9.4 37.1

 

Rockford Mean Number of Days (1991-2020)
Temperatures JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC ANNUAL
HIGHS >=90 - - - - 0.7 3.9 5.4 3.2 1.5 0.1 - - 14.8
HIGHS >=50 1.3 2.1 11.7 24.4 30.7 30.0 31.0 31.0 30.0 27.3 12.1 2.5 234.1
HIGHS <=32 18.5 12.6 3.7 0.1 - - - - - - 2.8 12.3 50.0
LOWS <=32 29.2 25.8 21.9 7.4 0.6 - - - 0.3 5.3 18.0 27.3 135.8
LOWS <=0 5.6 3.1 0.4 - - - - - - - - 2.4 11.5

 


Click here for the old 1981 to 2010 Normals for Chicago and Rockford