Decatur weather live forecast

Today's maximum temperature in Decatur is expected to be 30°C. Select a day from the live weather forecast for Decatur, Illinois, USA for more weather parameters.

Wednesday
5th Aug
30

20

7

7
Thursday
6th Aug
26

21

2

5
Friday
7th Aug
28

21

5

7
Saturday
8th Aug
29

21

6

6
Sunday
9th Aug
31

21

7

8

5-day weather forecast updated at 04:01 on Wednesday 5th August 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 Wednesday 5th August 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 30°C, moderate levels of heat & humidity, maximum UV of 7 (High) and 7 hours of bright sunshine. There are 2-5 mm of rainfall expected with 48% chance of some rain and a gentle breeze of 15 kph from the south.

30
°C maximum temperature
20
°C minimum temperature
isolated thunderstorms
7
hours of sunshine
7
UV index (High)
48
% chance of some rain
<5
mm of rainfall expected
M
moderate heat & humidity
15
kph wind from S

Decatur weather for Thursday 6th August 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 26°C, low levels of heat & humidity, maximum UV of 5 (Moderate) and 2 hours of bright sunshine. There are 20-30 mm of rainfall expected with 95% chance of some rain and a gentle breeze of 13 kph from the south-west.

26
°C maximum temperature
21
°C minimum temperature
isolated thunderstorms
2
hours of sunshine
5
UV index (Moderate)
95
% chance of some rain
<30
mm of rainfall expected
L
low heat & humidity
13
kph wind from SW

Decatur weather for Friday 7th August 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 28°C, low levels of heat & humidity, maximum UV of 7 (High) and 5 hours of bright sunshine. There are 2-5 mm of rainfall expected with 52% chance of some rain and a gentle breeze of 14 kph from the south-west.

28
°C maximum temperature
21
°C minimum temperature
isolated thunderstorms
5
hours of sunshine
7
UV index (High)
52
% chance of some rain
<5
mm of rainfall expected
L
low heat & humidity
14
kph wind from SW

Decatur weather for Saturday 8th August 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 29°C, moderate levels of heat & humidity, maximum UV of 6 (High) and 6 hours of bright sunshine. There are 2-5 mm of rainfall expected with 31% chance of some rain and a gentle breeze of 13 kph from the south-west.

29
°C maximum temperature
21
°C minimum temperature
isolated thunderstorms
6
hours of sunshine
6
UV index (High)
31
% chance of some rain
<5
mm of rainfall expected
M
moderate heat & humidity
13
kph wind from SW

Decatur weather for Sunday 9th August 2026

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 31°C, moderate levels of heat & humidity, maximum UV of 8 (Very High) and 7 hours of bright sunshine. There are 2-5 mm of rainfall expected with 34% chance of some rain and a gentle breeze of 18 kph from the south.