Official 1981-2010 Climate Normals City: WINCHESTER State: IL ID: 119331 Latitude: 39.6319 Longitude: -90.4572 Elevation: 509.7 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 35.3 40.5 52.3 65.5 74.5 83.3 86.9 86.4 79.5 67.3 53.0 38.9 Mean: 26.7 31.2 41.8 53.4 63.4 72.6 76.1 74.8 66.5 54.8 42.8 30.3 Low: 18.1 22.0 31.2 41.3 52.3 61.9 65.3 63.1 53.5 42.3 32.5 21.6 CDD: 0 0 2 14 79 243 345 305 117 19 1 0 HDD: 1187 945 722 362 129 15 1 3 72 335 668 1077 Number of Days T090: 0.0 0.0 0.0 0.0 0.6 5.3 9.7 8.3 2.1 0.2 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.1 0.5 0.3 0.0 0.0 0.0 0.0 T000: 2.7 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.1 T032: 27.6 23.4 18.8 4.8 0.3 0.0 0.0 0.0 0.1 5.1 15.7 25.7 ------------------------------------------------------------------------------------------ Annual Values High Temp: 63.7 F Mean Temp: 53.0 F Low Temp: 42.2 F Cooling DD: 1124 Heating DD: 5516 Days above 90 (T090): 26.2 Days above 100 (T100): 0.9 Days below 0 (T000): 4.4 Days below 32 (T032): 121.5 ------------------------------------------------------------------------------------------ Precipitation-Related Pseudonormals For stations with short records, linear combinations of normals from nearby sites were used to compute so-called pseudonormals. Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Prcp: 1.99 1.96 2.99 3.78 4.60 4.66 4.01 3.65 3.29 3.05 3.55 2.53 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 40.06 inches ------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------ 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