Official 1981-2010 Climate Normals City: DECATUR AP State: IL ID: 003887 Latitude: 39.8344 Longitude: -88.8656 Elevation: 674.7 ft Temperature-Related Normals Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec High: 35.2 39.2 51.4 63.8 74.2 82.6 86.5 84.4 78.6 65.9 51.7 38.8 Mean: 27.3 31.0 41.6 52.8 62.8 72.1 75.7 73.6 66.5 54.5 42.9 30.8 Low: 19.4 22.9 31.8 41.8 51.4 61.6 65.0 62.7 54.3 43.0 34.1 22.9 CDD: 0 0 1 13 73 229 333 269 111 19 0 0 HDD: 1168 950 727 379 141 17 1 5 67 345 663 1058 Number of Days T090: 0.0 0.0 0.0 0.0 0.7 3.8 8.5 5.1 1.9 0.3 0.0 0.0 T100: 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 T000: 1.7 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.9 T032: 26.8 23.5 16.6 5.0 0.3 0.0 0.0 0.0 0.0 2.9 13.8 24.5 ------------------------------------------------------------------------------------------ Annual Values High Temp: 62.8 F Mean Temp: 52.7 F Low Temp: 42.7 F Cooling DD: 1049 Heating DD: 5522 Days above 90 (T090): 20.3 Days above 100 (T100): 0.0 Days below 0 (T000): 2.8 Days below 32 (T032): 113.4 ------------------------------------------------------------------------------------------ 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: 1.74 1.98 2.64 3.80 4.29 4.35 3.86 3.65 2.89 3.28 3.43 2.54 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 38.45 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