Weather World
Lake Decatur, IL 7-Day Weather Forecast
Quick Weather Clicks
Settings
Sun & Moon
Lake Decatur Weather Forecast
Lake Decatur, IL Weather Forecast Date: 153 AM CDT Mon Aug 10 2026
Weather forecast for Lake Decatur, IL
Tonight Lo: 79°F Lo: 26°C |
Tonight... Mostly clear with a slight chance of showers and thunderstorms. Near steady temperature in the upper 70s. South winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 20%. |
Mon Hi: 90°FHi: 32°C Lo: 75°F Lo: 24°C |
Monday... Partly sunny with a slight chance of thunderstorms. A chance of showers, mainly in the morning. Humid with highs around 90. Southwest winds around 10 mph with gusts up to 25 mph. Chance of rain 30%. Heat index values up to 102. |
| Tue Hi: 91°FHi: 33°C Lo: 71°F Lo: 22°C |
Tuesday... Mostly sunny. A chance of showers and thunderstorms in the morning. Humid with highs in the lower 90s. Southwest winds 10 to 15 mph. Chance of rain 40%. Heat index values up to 104 in the afternoon. |
| Wed Hi: 89°FHi: 32°C Lo: 69°F Lo: 21°C |
Wednesday... Mostly sunny with a chance of showers. A chance of thunderstorms in the afternoon. Highs in the upper 80s. Chance of rain 50%. |
| Thu Hi: 81°FHi: 27°C Lo: 69°F Lo: 21°C |
Thursday... Showers likely with a chance of thunderstorms. Highs in the lower 80s. Lows in the upper 60s. Chance of rain 70%. |
Fri Hi: 81°FHi: 27°C Lo: 69°F Lo: 21°C |
Friday... A chance of showers in the morning. Mostly cloudy. Highs in the lower 80s. Chance of rain 40%. |
| Sat Hi: 85°FHi: 29°C Lo: 69°F Lo: 21°C |
Saturday... A chance of showers in the morning. Partly sunny. Highs in the mid 80s. Chance of rain 40%. |
Lake Decatur Radar Loop
Use the map search tool if you want to place a location marker on the radar map...