Official 1981-2010 Climate Normals City: ALTONA State: IL ID: 110140 Latitude: 41.1203 Longitude: -90.1644 Elevation: 734.7 ft Temperature-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 High: 30.1 34.8 48.3 61.5 72.3 81.0 84.3 81.9 75.9 63.6 48.1 33.7 Mean: 21.7 25.7 37.6 49.8 60.7 70.1 73.3 71.0 63.5 51.6 38.4 25.7 Low: 13.3 16.5 26.9 38.1 49.1 59.1 62.3 60.1 51.1 39.6 28.7 17.6 CDD: 0 0 0 2 40 171 260 192 54 10 0 0 HDD: 1342 1101 850 458 173 20 3 7 100 426 798 1219 Number of Days T090: 0.0 0.0 0.0 0.0 0.6 1.2 5.0 1.5 0.7 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: 4.8 2.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.4 T032: 29.0 26.0 22.7 7.3 0.0 0.0 0.0 0.0 0.0 5.8 18.9 26.5 ------------------------------------------------------------------------------------------ Annual Values High Temp: 59.7 F Mean Temp: 49.2 F Low Temp: 38.6 F Cooling DD: 729 Heating DD: 6496 Days above 90 (T090): 9.2 Days above 100 (T100): 0.0 Days below 0 (T000): 10.0 Days below 32 (T032): 136.3 ------------------------------------------------------------------------------------------ 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: 1.62 1.79 2.91 3.73 4.37 4.38 4.09 3.91 3.44 2.87 2.86 2.16 ------------------------------------------------------------------------------------------ Annual Values Precipitation: 38.13 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