10-Day Weather Forecast - Alton, IL

Sunny. A chance of showers and thunderstorms in the afternoon. Warmer with highs in the upper 90s. Southwest winds 5 to 10 mph. Chance of rain 50 percent. Heat index values up to 106.

Mostly cloudy with scattered showers and thunderstorms. Humid with lows in the lower 70s. Southeast winds around 5 mph. Chance of rain 50 percent. Heat index values up to 102 early in the evening.

Mostly sunny. A chance of showers and thunderstorms, mainly in the morning. Hot with highs in the mid 90s. East winds around 5 mph, becoming south around 5 mph in the afternoon. Chance of rain 50 percent. Heat index values up to 105.

Mostly clear. Lows in the mid 70s. South winds around 5 mph. Heat index values up to 101 early in the evening.

Mostly clear. Hot. Highs in the mid 90s. Heat index values up to 105.

Mostly clear. Hot. Lows in the lower 70s. Heat index values up to 105.

Mostly clear. Hot. Highs in the mid 90s. Heat index values up to 105.

Mostly clear. Hot. Lows in the lower 70s. Heat index values up to 105.

Mostly clear. Hot. Highs in the mid 90s. Heat index values up to 105.

Partly cloudy. A slight chance of showers after midnight. Lows in the lower 70s. Chance of rain 20 percent.

Mostly sunny with a slight chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the upper 80s. Chance of rain 20 percent.

Partly cloudy. A chance of showers with a slight chance of thunderstorms in the evening, then a slight chance of showers after midnight. Lows in the mid 60s. Chance of rain 30 percent.

Partly sunny with a chance of showers. A slight chance of thunderstorms in the afternoon. Highs in the lower 80s. Chance of rain 30 percent.

Mostly clear with a slight chance of rain. Chance of precipitation 25%. Low temperature around 62F. Dew point will be around 63F with an average humidity of 83%. Winds will be 5 mph from the N.

Mostly sunny. High temperature around 79F. Dew point will be around 61F with an average humidity of 68%. Winds will be 4 mph from the N.

Clear. Low temperature around 61F. Dew point will be around 59F with an average humidity of 77%. Winds will be 5 mph from the N.

Sunny. High temperature around 79F. Dew point will be around 58F with an average humidity of 63%. Winds will be 5 mph from the N.

Clear. Low temperature around 59F. Dew point will be around 56F with an average humidity of 71%. Winds will be 4 mph from the NE.