Decatur weather by month

Check out Decatur weather averages by month. Compare detailed monthly climate statistics including temperature, rainfall and sunshine figures.

Temperature in Decatur (°F)

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max temperature (daytime)
34°F maximum daytime temperature in January in Decatur34
39°F maximum daytime temperature in February in Decatur39
52°F maximum daytime temperature in March in Decatur52
64°F maximum daytime temperature in April in Decatur64
75°F maximum daytime temperature in May in Decatur75
84°F maximum daytime temperature in June in Decatur84
88°F maximum daytime temperature in July in Decatur88
84°F maximum daytime temperature in August in Decatur84
79°F maximum daytime temperature in September in Decatur79
68°F maximum daytime temperature in October in Decatur68
52°F maximum daytime temperature in November in Decatur52
37°F maximum daytime temperature in December in Decatur37
Min temperature (night-time)
16°F minimum night-time temperature in January in Decatur16
19°F minimum night-time temperature in February in Decatur19
30°F minimum night-time temperature in March in Decatur30
41°F minimum night-time temperature in April in Decatur41
52°F minimum night-time temperature in May in Decatur52
61°F minimum night-time temperature in June in Decatur61
64°F minimum night-time temperature in July in Decatur64
63°F minimum night-time temperature in August in Decatur63
55°F minimum night-time temperature in September in Decatur55
43°F minimum night-time temperature in October in Decatur43
34°F minimum night-time temperature in November in Decatur34
21°F minimum night-time temperature in December in Decatur21
Heat & Humidity
No heat & humidity in January in Decatur0
No heat & humidity in February in Decatur0
No heat & humidity in March in Decatur0
No heat & humidity in April in Decatur0
No heat & humidity in May in Decatur0
Moderate heat & humidity in June in DecaturM
High heat & humidity in July in DecaturH
Moderate heat & humidity in August in DecaturM
Low heat & humidity in September in DecaturL
No heat & humidity in October in Decatur0
No heat & humidity in November in Decatur0
No heat & humidity in December in Decatur0

Note: 0 = None, L = Low, M = Moderate, H = High, VH = Very high, E = Extreme

Sunshine & Daylight in Decatur

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daily hours of sunshine
Daily hours of daylight
10 hours of daylight per day in January in Decatur10
11 hours of daylight per day in February in Decatur11
12 hours of daylight per day in March in Decatur12
13 hours of daylight per day in April in Decatur13
14 hours of daylight per day in May in Decatur14
15 hours of daylight per day in June in Decatur15
15 hours of daylight per day in July in Decatur15
14 hours of daylight per day in August in Decatur14
12 hours of daylight per day in September in Decatur12
11 hours of daylight per day in October in Decatur11
10 hours of daylight per day in November in Decatur10
9 hours of daylight per day in December in Decatur9
UV Index (Maximum)
UV (maximum) index 2 (Low) in January in Decatur2
UV (maximum) index 3 (Moderate) in February in Decatur3
UV (maximum) index 4 (Moderate) in March in Decatur4
UV (maximum) index 6 (High) in April in Decatur6
UV (maximum) index 8 (Very High) in May in Decatur8
UV (maximum) index 9 (Very High) in June in Decatur9
UV (maximum) index 9 (Very High) in July in Decatur9
UV (maximum) index 8 (Very High) in August in Decatur8
UV (maximum) index 6 (High) in September in Decatur6
UV (maximum) index 4 (Moderate) in October in Decatur4
UV (maximum) index 2 (Low) in November in Decatur2
UV (maximum) index 2 (Low) in December in Decatur2

Rainfall in Decatur

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Number of days with some rain
10 days with some rainfall in January in Decatur10
9 days with some rainfall in February in Decatur9
12 days with some rainfall in March in Decatur12
12 days with some rainfall in April in Decatur12
10 days with some rainfall in May in Decatur10
9 days with some rainfall in June in Decatur9
9 days with some rainfall in July in Decatur9
8 days with some rainfall in August in Decatur8
8 days with some rainfall in September in Decatur8
8 days with some rainfall in October in Decatur8
10 days with some rainfall in November in Decatur10
11 days with some rainfall in December in Decatur11
Average monthly rainfall (inches)
1.9 inches monthly rainfall in January in Decatur1.9
1.9 inches monthly rainfall in February in Decatur1.9
3.1 inches monthly rainfall in March in Decatur3.1
3.8 inches monthly rainfall in April in Decatur3.8
4.0 inches monthly rainfall in May in Decatur4.0
3.9 inches monthly rainfall in June in Decatur3.9
4.2 inches monthly rainfall in July in Decatur4.2
3.7 inches monthly rainfall in August in Decatur3.7
3.2 inches monthly rainfall in September in Decatur3.2
2.8 inches monthly rainfall in October in Decatur2.8
3.0 inches monthly rainfall in November in Decatur3.0
2.8 inches monthly rainfall in December in Decatur2.8

More about Decatur

Decatur by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

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The climate guide for Illinois (Decatur) shows long term monthly weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

What's the climate like in Decatur?

Decatur has a cold climate with hot summers and some rainfall in all months.

Metric (°C)  |  Imperial (°F)

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Tropical storm risk: Decatur, Illinois hurricane season

% of month affected by tropical storms
0
0
0
0
0
0
0
0
0
0
0
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

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More about the USA

Compare Decatur with the USA

Below the Decatur chart shows average maximum daytime temperature for Decatur, Illinois, USA and the USA (Washington).

Maximum daytime temperature (°F)

Decatur, Illinois, USA
USA (Washington)
34
41
39
45
52
55
64
66
75
75
84
84
88
88
84
86
79
79
68
68
52
57
37
46
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Metric (°C)  |  Imperial (°F)

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