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 (°C)

  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max temperature (daytime)
1°C maximum daytime temperature in January in Decatur1
4°C maximum daytime temperature in February in Decatur4
11°C maximum daytime temperature in March in Decatur11
18°C maximum daytime temperature in April in Decatur18
24°C maximum daytime temperature in May in Decatur24
29°C maximum daytime temperature in June in Decatur29
31°C maximum daytime temperature in July in Decatur31
29°C maximum daytime temperature in August in Decatur29
26°C maximum daytime temperature in September in Decatur26
20°C maximum daytime temperature in October in Decatur20
11°C maximum daytime temperature in November in Decatur11
3°C maximum daytime temperature in December in Decatur3
Min temperature (night-time)
-9°C minimum night-time temperature in January in Decatur-9
-7°C minimum night-time temperature in February in Decatur-7
-1°C minimum night-time temperature in March in Decatur-1
5°C minimum night-time temperature in April in Decatur5
11°C minimum night-time temperature in May in Decatur11
16°C minimum night-time temperature in June in Decatur16
18°C minimum night-time temperature in July in Decatur18
17°C minimum night-time temperature in August in Decatur17
13°C minimum night-time temperature in September in Decatur13
6°C minimum night-time temperature in October in Decatur6
1°C minimum night-time temperature in November in Decatur1
-6°C minimum night-time temperature in December in Decatur-6
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 (mm)
49 mm monthly rainfall in January in Decatur49
48 mm monthly rainfall in February in Decatur48
80 mm monthly rainfall in March in Decatur80
96 mm monthly rainfall in April in Decatur96
102 mm monthly rainfall in May in Decatur102
100 mm monthly rainfall in June in Decatur100
107 mm monthly rainfall in July in Decatur107
93 mm monthly rainfall in August in Decatur93
81 mm monthly rainfall in September in Decatur81
70 mm monthly rainfall in October in Decatur70
77 mm monthly rainfall in November in Decatur77
72 mm monthly rainfall in December in Decatur72

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 / mm)  |  Imperial (°F / inches)

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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 (°C)

Decatur, Illinois, USA
USA (Washington)
1
5
4
7
11
13
18
19
24
24
29
29
31
31
29
30
26
26
20
20
11
14
3
8
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Metric (°C / mm)  |  Imperial (°F / inches)

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