Official 1981-2010 Climate Normals
City: DECATUR AIRPORT
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
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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
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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
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Annual Values
Precipitation: 38.45 inches
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City: DECATUR WTP
State: IL
ID: 112193
Latitude: 39.8289
Longitude: -88.9506
Elevation: 619.9 ft
Temperature-Related Normals
Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
High: 36.0 41.1 53.1 66.0 75.9 84.5 87.4 86.1 80.0 67.7 53.1 39.4
Mean: 27.5 32.2 42.7 54.4 64.2 73.3 76.5 75.1 67.8 56.2 43.8 31.2
Low: 19.1 23.2 32.3 42.9 52.5 62.0 65.6 64.1 55.6 44.7 34.4 23.1
CDD: 0 0 2 19 88 259 357 317 147 25 1 0
HDD: 1161 920 693 336 112 12 0 4 63 298 639 1046
Number of Days
T090: 0.0 0.0 0.0 0.1 0.9 6.3 9.6 7.9 3.3 0.1 0.0 0.0
T100: 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.4 0.0 0.0 0.0 0.0
T000: 2.7 1.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.2
T032: 26.6 22.0 15.8 3.7 0.1 0.0 0.0 0.0 0.2 3.2 13.1 24.4
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Annual Values
High Temp: 64.3 F
Mean Temp: 53.8 F
Low Temp: 43.4 F
Cooling DD: 1216
Heating DD: 5284
Days above 90 (T090): 28.1
Days above 100 (T100): 0.8
Days below 0 (T000): 5.1
Days below 32 (T032): 109.2
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Precipitation-Related Normals
Normal Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Prcp: 2.14 2.00 2.59 3.67 4.79 4.50 3.98 3.77 3.14 3.25 3.71 2.78
Snow: 4.8 4.2 1.7 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.2 4.9
Number of Days
P001: 8.5 7.3 9.7 10.6 12.1 9.9 9.2 7.3 7.5 8.7 9.4 9.7
P010: 4.5 4.1 6.3 6.6 7.6 6.6 6.2 5.2 4.7 5.6 6.2 5.6
P100: 0.6 0.5 0.4 0.9 1.3 1.3 1.2 1.2 0.8 1.0 0.9 0.4
S001: 3.7 2.6 0.9 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.3 2.6
S010: 2.2 1.5 0.6 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 1.8
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
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Annual Values
Precipitation: 40.32 inches
Snowfall: 16.0 inches
Days precipitation at or above 0 inches (P000): 109.9
Days precipitation at or above 0.10 inches (P010): 69.2
Days Precipitation at or above 1.00 inches (P100): 10.5
Days Snowfall at or above 0.1 inches (S001): 10.3
Days Snowfall at or above 1.0 inches (S010): 6.3
Days Snowfall at or above 10.0 inches (S100): 0.0
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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
