Official 1981-2010 Climate Normals City: GRAND CHAIN DAM State: IL ID: 113580 Latitude: 37.2036 Longitude: -89.0422 Elevation: 384.7 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 42.1 46.7 56.7 67.3 75.8 84.3 88.6 88.1 81.9 70.1 57.7 44.8 Mean: 33.8 38.1 46.4 56.5 65.8 73.9 78.5 77.8 70.8 59.0 48.3 36.9 Low: 25.6 29.6 36.2 45.8 55.8 63.5 68.3 67.5 59.7 47.9 38.9 28.9 CDD: 0 0 1 17 100 275 417 397 200 36 2 0 HDD: 966 752 576 271 75 8 1 0 27 222 503 872 Number of Days T090: 0.0 0.0 0.0 0.0 0.3 5.2 13.1 11.5 2.7 0.1 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 T000: 0.3 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 T032: 22.4 17.0 9.9 2.3 0.0 0.0 0.0 0.0 0.0 1.1 6.6 19.1 ------------------------------------------------------------------------------------------ Annual Values High Temp: 67.1 F Mean Temp: 57.3 F Low Temp: 47.4 F Cooling DD: 1447 Heating DD: 4273 Days above 90 (T090): 32.9 Days above 100 (T100): 0.4 Days below 0 (T000): 0.4 Days below 32 (T032): 78.4 ------------------------------------------------------------------------------------------ Precipitation-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 3.85 3.90 4.48 4.81 4.96 4.30 3.36 2.87 3.30 4.06 4.51 4.60 Snow: 2.1 3.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 1.8 Number of Days P001: 9.6 8.6 9.7 10.2 10.5 9.3 7.5 5.8 7.2 7.3 8.4 9.9 P010: 6.7 6.1 7.4 7.3 8.5 7.0 5.2 4.4 5.0 5.3 6.3 6.9 P100: 1.1 0.7 1.2 1.3 1.6 1.3 1.2 0.9 1.1 1.2 1.1 1.0 S001: 1.1 1.5 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.8 S010: 0.7 0.9 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.6 S100: 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 49.00 inches Snowfall: 8.0 inches Days precipitation at or above 0 inches (P000): 104.0 Days precipitation at or above 0.10 inches (P010): 76.1 Days Precipitation at or above 1.00 inches (P100): 13.7 Days Snowfall at or above 0.1 inches (S001): 3.7 Days Snowfall at or above 1.0 inches (S010): 2.4 Days Snowfall at or above 10.0 inches (S100): 0.2 ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------ 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