Official 1981-2010 Climate Normals City: VANDALIA State: IL ID: 118781 Latitude: 38.9703 Longitude: -89.0922 Elevation: 539.9 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 36.3 41.5 52.6 64.9 74.3 83.6 87.0 86.0 79.2 67.1 53.9 40.1 Mean: 28.3 32.7 42.8 54.1 63.8 73.2 76.8 75.2 67.1 55.3 44.3 31.9 Low: 20.3 23.9 33.0 43.2 53.2 62.7 66.6 64.4 55.1 43.4 34.7 23.8 CDD: 0 0 2 17 83 258 366 319 133 18 1 0 HDD: 1138 904 691 346 122 14 1 3 68 321 623 1024 Number of Days T090: 0.0 0.0 0.0 0.0 0.5 5.5 9.5 8.5 2.0 0.0 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 T000: 1.7 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 T032: 26.4 22.2 15.1 3.3 0.0 0.0 0.0 0.0 0.1 3.3 12.6 24.7 ------------------------------------------------------------------------------------------ Annual Values High Temp: 64.0 F Mean Temp: 53.9 F Low Temp: 43.8 F Cooling DD: 1198 Heating DD: 5253 Days above 90 (T090): 26.1 Days above 100 (T100): 0.6 Days below 0 (T000): 3.2 Days below 32 (T032): 107.7 ------------------------------------------------------------------------------------------ Precipitation-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 2.63 2.55 3.24 3.70 5.00 4.15 3.60 3.20 2.85 3.24 4.02 3.09 Snow: 4.4 2.9 1.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 2.7 Number of Days P001: 8.0 6.9 9.2 10.4 11.5 9.5 7.7 6.8 6.6 8.0 8.7 8.3 P010: 5.1 4.5 6.1 7.6 8.3 7.3 5.7 5.1 4.7 5.8 6.5 5.5 P100: 0.7 0.7 0.9 0.9 1.5 1.3 1.3 0.7 0.9 0.9 1.1 0.9 S001: 2.4 1.9 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 1.9 S010: 1.7 1.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 1.3 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: 41.27 inches Snowfall: 12.0 inches Days precipitation at or above 0 inches (P000): 101.6 Days precipitation at or above 0.10 inches (P010): 72.2 Days Precipitation at or above 1.00 inches (P100): 11.8 Days Snowfall at or above 0.1 inches (S001): 7.1 Days Snowfall at or above 1.0 inches (S010): 4.7 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