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Decatur, IL weather and climate

Macon County, IL · population 70,368 · about 689 ft elevation

Everything below is a 30 year average for 1991-2020, computed from daily climate history at Decatur's own coordinates.

The year at a glance

Sunny days
194
clear or partly cloudy, per year
Precipitation
41 in
per year
Wet days
120
rain or snow per year
Snowfall
14 in
per year
Hot days
26
above 90 °F
Freezing nights
110
at or below 32 °F
Humidity
69%
average relative
Average temperature
53 °F
year round

Monthly temperatures

Average daily high and low for each month, in °F.

Daily highDaily low
20406080JanMarMayJulSepNovDaily high, Jan: 34 °FDaily high, Feb: 39 °FDaily high, Mar: 51 °FDaily high, Apr: 64 °FDaily high, May: 74 °FDaily high, Jun: 82 °FDaily high, Jul: 85 °FDaily high, Aug: 84 °FDaily high, Sep: 78 °FDaily high, Oct: 65 °FDaily high, Nov: 51 °FDaily high, Dec: 39 °FDaily low, Jan: 20 °FDaily low, Feb: 24 °FDaily low, Mar: 33 °FDaily low, Apr: 43 °FDaily low, May: 54 °FDaily low, Jun: 63 °FDaily low, Jul: 66 °FDaily low, Aug: 64 °FDaily low, Sep: 56 °FDaily low, Oct: 45 °FDaily low, Nov: 34 °FDaily low, Dec: 25 °F
View monthly temperatures as a table
Monthly temperatures (°F)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Daily high343951647482858478655139
Daily low202433435463666456453425

Monthly precipitation

Total rain plus melted snow for each month, in inches.

0.02.04.0JanMarMayJulSepNovDecatur, Jan: 2.7 inDecatur, Feb: 2.3 inDecatur, Mar: 3.3 inDecatur, Apr: 4.6 inDecatur, May: 4.8 inDecatur, Jun: 4.3 inDecatur, Jul: 3.6 inDecatur, Aug: 3.0 inDecatur, Sep: 3.2 inDecatur, Oct: 3.5 inDecatur, Nov: 3.5 inDecatur, Dec: 2.5 in
View monthly precipitation as a table
Monthly precipitation (inches)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Decatur2.72.33.34.64.84.33.63.03.23.53.52.5

Monthly sunny days

Days each month with clear or partly cloudy skies.

01020JanMarMayJulSepNovDecatur, Jan: 13 daysDecatur, Feb: 12 daysDecatur, Mar: 14 daysDecatur, Apr: 14 daysDecatur, May: 15 daysDecatur, Jun: 17 daysDecatur, Jul: 21 daysDecatur, Aug: 21 daysDecatur, Sep: 21 daysDecatur, Oct: 18 daysDecatur, Nov: 16 daysDecatur, Dec: 13 days
View monthly sunny days as a table
Monthly sunny days (days)
CityJanFebMarAprMayJunJulAugSepOctNovDec
Decatur131214141517212121181613

Compare Decatur with another city

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See weather for every covered Illinois city

About this data

Figures are 30 year averages for 1991-2020. Wet days count days with measurable precipitation, calibrated against the wet day counts in NOAA's published climate normals. Sunny days count clear plus partly cloudy days, defined as average cloud cover of 63 percent or less and calibrated against NOAA's published sky cover tables. Snowfall figures are model estimates anchored to NOAA station measurements near each city.

Weather data by Open-Meteo.com (CC BY 4.0). Contains modified Copernicus Climate Change Service information (ERA5, ERA5-Land).