Official 1981-2010 Climate Normals City: CHICAGO OHARE AP State: IL ID: 094846 Latitude: 41.9950 Longitude: -87.9336 Elevation: 658.0 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 31.0 35.3 46.6 59.0 70.0 79.7 84.1 81.9 74.8 62.3 48.2 34.8 Mean: 23.8 27.7 37.9 48.9 59.1 68.9 74.0 72.4 64.6 52.5 40.3 27.7 Low: 16.5 20.1 29.2 38.8 48.3 58.1 63.9 62.9 54.3 42.8 32.4 20.7 CDD: 0 0 1 9 44 165 283 238 92 11 0 0 HDD: 1279 1044 841 492 225 48 4 9 105 397 741 1155 Number of Days T090: 0.0 0.0 0.0 0.0 0.5 3.0 5.9 3.6 1.0 0.0 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.1 0.3 0.0 0.0 0.0 0.0 0.0 T000: 3.8 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.5 T032: 28.0 24.0 19.6 6.3 0.3 0.0 0.0 0.0 0.1 3.5 14.0 26.0 ------------------------------------------------------------------------------------------ Annual Values High Temp: 59.1 F Mean Temp: 49.9 F Low Temp: 40.8 F Cooling DD: 842 Heating DD: 6339 Days above 90 (T090): 14.0 Days above 100 (T100): 0.4 Days below 0 (T000): 7.1 Days below 32 (T032): 121.8 ------------------------------------------------------------------------------------------ Precipitation-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 1.73 1.79 2.50 3.38 3.68 3.45 3.70 4.90 3.21 3.15 3.15 2.25 Snow: 10.8 9.1 5.6 1.2 0.0 0.0 0.0 0.0 0.0 0.3 1.2 8.5 Number of Days P001: 10.5 8.8 11.1 12.0 11.6 10.2 9.8 9.8 8.3 10.2 10.8 11.0 P010: 4.7 4.4 5.5 6.4 7.2 5.9 6.0 6.7 5.4 5.9 6.0 5.0 P100: 0.1 0.3 0.4 0.8 0.8 0.9 1.0 1.5 0.8 0.6 0.8 0.3 S001: 8.2 6.1 4.3 0.9 0.0 0.0 0.0 0.0 0.0 0.2 1.7 7.1 S010: 3.7 2.8 1.7 0.3 0.0 0.0 0.0 0.0 0.0 0.1 0.4 2.6 S100: 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 36.89 inches Snowfall: 36.7 inches Days precipitation at or above 0 inches (P000): 124.1 Days precipitation at or above 0.10 inches (P010): 69.1 Days Precipitation at or above 1.00 inches (P100): 8.3 Days Snowfall at or above 0.1 inches (S001): 28.5 Days Snowfall at or above 1.0 inches (S010): 11.6 Days Snowfall at or above 10.0 inches (S100): 0.1 ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------ KEY: High - average daily high temperature, degrees F Mean - average daily mean temperature, degrees F Low - average daily low temperature, degrees F CDD - cooling degree days, base 50F HDD - heating degree days, base 50F T090 - number of Days with Temperatures above 90 degrees F T100 - number of Days with Temperatures above 100 degrees F T000 - number of Days with Temperatures below 0 degrees F T032 - number of Days with Temperatures below 32 degrees F Prcp - precipitation, inches Snow - snowfall, inches P001 - number of Days with Precipitation of 0.01 inches or more P010 - number of Days with Precipitation of 0.10 inches or more P100 - number of Days with Precipitation of 1.00 inches or more S001 - number of Days with Snowfall of 0.1 inches or more S010 - number of Days with Snowfall of 1.0 inches or more S100 - number of Days with Snowfall of 10.0 inches or more Page Source: Dr. Jim Angel, State Climatologist Illinois State Water Survey Prairie Research Institute University of Illinois Data Source: NOAA National Climatic Data Center