10-Day Weather Forecast - O'Fallon, IL

Sunny. Not as cool with highs in the upper 30s. South winds 5 to 10 mph.

Mostly cloudy. Not as cool with lows in the mid 20s. Southwest winds around 5 mph.

Partly sunny. Highs in the upper 30s. Northwest winds around 5 mph becoming north around 5 mph in the afternoon.

Mostly cloudy. A slight chance of snow after midnight. Lows in the upper 20s. East winds around 5 mph. Chance of snow 20 percent.

Mostly cloudy. A chance of rain and snow mainly in the morning. Highs in the mid 30s. Chance of precipitation 30 percent.

Mostly cloudy. Cooler with lows around 15.

Partly cloudy. Highs in the lower 30s. Lows in the lower 20s.

Partly cloudy. Highs in the lower 30s. Lows in the lower 20s.

Mostly sunny. Not as cool with highs in the mid 40s.

Mostly cloudy. Near steady temperature in the mid 30s. Temperature rising into the upper 30s after midnight.

Mostly cloudy with a 40 percent chance of rain. Highs in the mid 40s.

Mostly cloudy. Lows in the lower 20s. Highs in the mid 30s.

Mostly cloudy. Lows in the lower 20s. Highs in the mid 30s.

Clear. Low temperature around 28F. Dew point will be around 21F with an average humidity of 69%. Winds will be 3 mph from the NW.

Sunny. High temperature around 36F. Dew point will be around 18F with an average humidity of 55%. Winds will be 4 mph from the W.

Clear. Low temperature around 28F. Dew point will be around 21F with an average humidity of 70%. Winds will be 2 mph from the NW.

Sunny. High temperature around 37F. Dew point will be around 21F with an average humidity of 60%. Winds will be 3 mph from the SW.

Clear. Low temperature around 34F. Dew point will be around 27F with an average humidity of 72%. Winds will be 4 mph from the S.