Decatur weather live forecast

Today's maximum temperature in Decatur is expected to be 34°C. Select a day from the live weather forecast for Decatur, Illinois, USA for more weather parameters.

5-day weather forecast updated at 04:01 on Sunday 17th August 2025 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 Sunday 17th August 2025

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 34°C, high levels of heat & humidity, maximum UV of 7 (High) and 9 hours of bright sunshine. There are 0-2 mm of rainfall expected with 14% chance of some rain and little or no wind of 5 kph from the south-west.

  • 34°C maximum temperature34
    °C maximum temperature
  • 24°C minimum temperature24
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 9 hours of bright sunshine9
    hours of sunshine
  • UV (maximum) index 7 (High)7
    UV index (High)
  • 14% chance of some rain14
    % chance of some rain
  • 0-2 mm of rainfall expected<2
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Little or no wind of 5 kph from the South-West5
    kph wind from SW

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Decatur weather for Monday 18th August 2025

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 32°C, high levels of heat & humidity, maximum UV of 7 (High) and 6 hours of bright sunshine. There are 2-5 mm of rainfall expected with 38% chance of some rain and little or no wind of 6 kph from the south-east.

  • 32°C maximum temperature32
    °C maximum temperature
  • 25°C minimum temperature25
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 6 hours of bright sunshine6
    hours of sunshine
  • UV (maximum) index 7 (High)7
    UV index (High)
  • 38% chance of some rain38
    % chance of some rain
  • 2-5 mm of rainfall expected<5
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Little or no wind of 6 kph from the South-East6
    kph wind from SE

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Decatur weather for Tuesday 19th August 2025

Expect isolated thunderstorms in Decatur, Illinois with a maximum temperature of 33°C, high levels of heat & humidity, maximum UV of 7 (High) and 7 hours of bright sunshine. There are 2-5 mm of rainfall expected with 51% chance of some rain and little or no wind of 5 kph from the south-west.

  • 33°C maximum temperature33
    °C maximum temperature
  • 25°C minimum temperature25
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 7 hours of bright sunshine7
    hours of sunshine
  • UV (maximum) index 7 (High)7
    UV index (High)
  • 51% chance of some rain51
    % chance of some rain
  • 2-5 mm of rainfall expected<5
    mm of rainfall expected
  • High heat & humidityH
    high heat & humidity
  • Little or no wind of 5 kph from the South-West5
    kph wind from SW

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Decatur weather for Wednesday 20th August 2025

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 0-2 mm of rainfall expected with 25% chance of some rain and a light breeze of 10 kph from the north.

  • 28°C maximum temperature28
    °C maximum temperature
  • 20°C minimum temperature20
    °C minimum temperature
  • Isolated thunderstorms
    isolated thunderstorms
  • 5 hours of bright sunshine5
    hours of sunshine
  • UV (maximum) index 7 (High)7
    UV index (High)
  • 25% chance of some rain25
    % chance of some rain
  • 0-2 mm of rainfall expected<2
    mm of rainfall expected
  • Low heat & humidityL
    low heat & humidity
  • Light breeze of 10 kph from the North10
    kph wind from N

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Decatur weather for Thursday 21st August 2025

Expect broken clouds in Decatur, Illinois with a maximum temperature of 28°C, low levels of heat & humidity, maximum UV of 6 (High) and 6 hours of bright sunshine. There are 0 mm of rainfall expected and a light breeze of 8 kph from the north-east.

  • 28°C maximum temperature28
    °C maximum temperature
  • 19°C minimum temperature19
    °C minimum temperature
  • Broken clouds
    broken clouds
  • 6 hours of bright sunshine6
    hours of sunshine
  • UV (maximum) index 6 (High)6
    UV index (High)
  • 0 mm of rainfall expected0
    mm of rainfall expected
  • Low heat & humidityL
    low heat & humidity
  • Light breeze of 8 kph from the North-East8
    kph wind from NE

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

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