62521 Weather (Decatur, IL)

Weather forecast for: Decatur IL

Last Update: 10:36 pm CDT Aug 13, 2026

Tonight: A 30 percent chance of showers and thunderstorms, mainly after 4am. Some of the storms could produce heavy rainfall. Mostly cloudy, with a low around 71. East wind around 8 mph.

Friday: A chance of showers and thunderstorms before 11am, then a slight chance of showers between 11am and noon. Mostly cloudy, then gradually becoming sunny, with a high near 92. Heat index values as high as 105. East southeast wind around 7 mph becoming south in the afternoon. Chance of precipitation is 40%.

Friday Night: Partly cloudy, with a low around 73. East wind around 8 mph.

Saturday: Mostly sunny, with a high near 93. Heat index values as high as 106. South southeast wind 6 to 9 mph becoming southwest in the afternoon. Winds could gust as high as 15 mph.

Saturday Night: Partly cloudy, with a low around 73. Southwest wind 5 to 7 mph.

Sunday: Partly sunny, with a high near 91. West wind 5 to 8 mph.

Sunday Night: Showers likely and possibly a thunderstorm before 1am. Mostly cloudy, with a low around 69. North wind 3 to 8 mph. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Monday: Mostly sunny, with a high near 84.

Monday Night: Partly cloudy, with a low around 65.

Tuesday: Sunny, with a high near 85.

Tuesday Night: Partly cloudy, with a low around 68.

Wednesday: Partly sunny, with a high near 89.

Wednesday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 68.

Thursday: Partly sunny, with a high near 85.