Official 1981-2010 Climate Normals City: JOLIET BRANDON RD State: IL ID: 114530 Latitude: 41.5033 Longitude: -88.1028 Elevation: 542.8 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 31.4 36.0 47.4 60.6 71.4 80.9 84.2 82.4 76.3 63.8 49.4 35.2 Mean: 24.0 28.2 38.4 49.9 60.1 70.3 74.1 72.5 65.4 53.2 41.3 28.1 Low: 16.6 20.4 29.3 39.2 48.7 59.7 63.9 62.7 54.5 42.7 33.2 20.9 CDD: 0 0 0 8 45 190 283 240 103 12 0 0 HDD: 1271 1030 827 461 199 31 3 6 91 376 711 1145 Number of Days T090: 0.0 0.0 0.0 0.0 0.8 3.2 5.5 3.1 1.2 0.0 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.1 0.2 0.0 0.0 0.0 0.0 0.0 T000: 4.0 1.8 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 T032: 27.4 23.6 19.9 5.6 0.3 0.0 0.0 0.0 0.0 2.8 13.4 25.5 ------------------------------------------------------------------------------------------ Annual Values High Temp: 60.0 F Mean Temp: 50.6 F Low Temp: 41.1 F Cooling DD: 882 Heating DD: 6151 Days above 90 (T090): 13.8 Days above 100 (T100): 0.3 Days below 0 (T000): 7.6 Days below 32 (T032): 118.4 ------------------------------------------------------------------------------------------ Precipitation-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 1.80 1.71 2.25 3.49 4.08 3.88 4.33 4.16 3.01 2.84 3.06 2.20 Number of Days P001: 10.7 8.9 10.6 11.4 11.4 10.1 9.4 9.0 8.2 9.5 10.8 11.3 P010: 4.4 4.5 5.3 6.7 7.7 6.5 6.2 5.7 5.0 5.4 5.8 5.2 P100: 0.3 0.3 0.4 0.7 0.8 0.8 1.1 1.1 0.9 0.5 0.7 0.3 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 36.81 inches Days precipitation at or above 0 inches (P000): 121.3 Days precipitation at or above 0.10 inches (P010): 68.4 Days Precipitation at or above 1.00 inches (P100): 7.9 ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------ 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