Official 1981-2010 Climate Normals City: MT VERNON 3 State: IL ID: 115943 Latitude: 38.3483 Longitude: -88.8533 Elevation: 490.0 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 38.1 43.1 53.5 64.9 73.8 82.9 86.3 85.6 78.6 67.4 54.5 41.3 Mean: 29.5 33.6 43.5 54.2 63.7 72.9 76.6 75.1 67.2 55.6 44.7 32.6 Low: 20.9 24.2 33.4 43.6 53.6 62.9 66.9 64.6 55.8 43.8 34.8 23.9 CDD: 0 0 2 18 79 249 360 316 134 20 1 0 HDD: 1100 878 670 341 120 12 1 3 68 311 612 1004 Number of Days T090: 0.0 0.0 0.0 0.0 0.1 3.7 7.5 7.5 2.1 0.1 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.2 0.0 0.0 0.0 0.0 T000: 1.4 0.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.1 T032: 26.0 21.6 14.8 3.6 0.0 0.0 0.0 0.0 0.1 4.3 12.6 23.9 ------------------------------------------------------------------------------------------ Annual Values High Temp: 64.3 F Mean Temp: 54.2 F Low Temp: 44.1 F Cooling DD: 1179 Heating DD: 5119 Days above 90 (T090): 21.0 Days above 100 (T100): 0.4 Days below 0 (T000): 3.3 Days below 32 (T032): 106.8 ------------------------------------------------------------------------------------------ Precipitation-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 2.34 2.85 3.87 4.36 5.16 3.88 3.68 2.96 3.22 3.65 4.21 3.22 Snow: 3.6 4.7 1.3 0.2 0.0 0.0 0.0 0.0 0.0 0.2 0.3 3.6 Number of Days P001: 8.2 8.3 10.8 11.3 12.6 10.3 8.5 7.8 7.8 9.0 10.2 10.1 P010: 4.6 5.1 6.8 7.7 8.0 6.8 5.5 4.6 4.8 5.9 6.9 6.2 P100: 0.5 0.7 1.0 1.2 1.3 1.0 1.4 0.9 0.8 1.0 1.3 0.7 S001: 2.4 2.0 0.6 0.1 0.0 0.0 0.0 0.0 0.0 0.1 0.2 1.5 S010: 1.6 1.5 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.1 0.1 1.1 S100: 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 43.40 inches Snowfall: 13.9 inches Days precipitation at or above 0 inches (P000): 114.9 Days precipitation at or above 0.10 inches (P010): 72.9 Days Precipitation at or above 1.00 inches (P100): 11.8 Days Snowfall at or above 0.1 inches (S001): 6.9 Days Snowfall at or above 1.0 inches (S010): 4.9 Days Snowfall at or above 10.0 inches (S100): 0.0 ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------ 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