Decatur weather live forecast

Today's maximum temperature in Decatur is expected to be 24°C. Select a day from the live weather forecast for Decatur, Illinois, USA for more weather parameters.

Saturday
16th May
24

18

1

6
Sunday
17th May
29

18

10

8
Monday
18th May
28

20

4

6
Tuesday
19th May
26

17

6

5
Wednesday
20th May
20

12

11

7

5-day weather forecast updated at 04:01 on Saturday 16th May 2026 GMT

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The 5-day weather forecast for Illinois (Decatur) is provided by the Swiss meteorological agency, meteoblue. Find out more about our data sources.

Decatur weather forecast by day

Below are the detailed weather forecasts for Decatur for the next 5 days.

Decatur weather for Saturday 16th May 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 24°C, maximum UV of 6 (High) and 1 hour of bright sunshine. There are 5-10 mm of rainfall expected with 79% chance of some rain and a moderate breeze of 21 kph from the south.

24
°C maximum temperature
18
°C minimum temperature
isolated thunderstorms
1
hour of sunshine
6
UV index (High)
79
% chance of some rain
<10
mm of rainfall expected
0
no heat & humidity
21
kph wind from S

Decatur weather for Sunday 17th May 2026

Expect scattered clouds in Decatur, Illinois with a maximum temperature of 29°C, low levels of heat & humidity, maximum UV of 8 (Very High) and 10 hours of bright sunshine. There are 0 mm of rainfall expected and a fresh breeze of 32 kph from the south.

29
°C maximum temperature
18
°C minimum temperature
scattered clouds
10
hours of sunshine
8
UV index (Very High)
0
mm of rainfall expected
L
low heat & humidity
32
kph wind from S

Decatur weather for Monday 18th May 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 28°C, low levels of heat & humidity, maximum UV of 6 (High) and 4 hours of bright sunshine. There are 5-10 mm of rainfall expected with 72% chance of some rain and a fresh breeze of 32 kph from the south.

28
°C maximum temperature
20
°C minimum temperature
isolated thunderstorms
4
hours of sunshine
6
UV index (High)
72
% chance of some rain
<10
mm of rainfall expected
L
low heat & humidity
32
kph wind from S

Decatur weather for Tuesday 19th May 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 26°C, maximum UV of 5 (Moderate) and 6 hours of bright sunshine. There are 10-20 mm of rainfall expected with 72% chance of some rain and a fresh breeze of 31 kph from the south-west.

26
°C maximum temperature
17
°C minimum temperature
isolated thunderstorms
6
hours of sunshine
5
UV index (Moderate)
72
% chance of some rain
<20
mm of rainfall expected
26
°C wind chill
31
kph wind from SW

Decatur weather for Wednesday 20th May 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 20°C, maximum UV of 7 (High) and 11 hours of bright sunshine. There are 2-5 mm of rainfall expected with 33% chance of some rain and a moderate breeze of 20 kph from the north.