10-Day Weather Forecast - O'Fallon, IL

Mostly sunny. Cooler with highs in the lower 40s. Northeast winds around 5 mph becoming east in the afternoon.

Partly cloudy. Lows around 30. Southeast winds 5 to 10 mph.

Partly sunny. Highs in the lower 50s. South winds 5 to 10 mph.

Partly cloudy in the evening then clearing. Not as cool. Near steady temperature in the upper 40s. South winds 5 to 10 mph.

Partly cloudy. Highs in the lower 60s. Lows in the lower 40s.

Partly cloudy. Highs in the lower 60s. Lows in the lower 40s.

Cloudy. Highs in the upper 60s.

Mostly cloudy in the evening then clearing. Not as cool with lows in the upper 50s.

Sunny. Highs in the lower 70s.

Partly cloudy in the evening then becoming mostly cloudy. Lows in the lower 50s.

Mostly cloudy. Highs in the mid 60s. Lows in the mid 40s.

Mostly cloudy. Highs in the mid 60s. Lows in the mid 40s.

Mostly cloudy. Highs in the upper 50s.

Cloudy with a slight chance of rain. Chance of precipitation 25%. Low temperature around 47F. Dew point will be around 46F with an average humidity of 82%. Winds will be 3 mph from the NW.

Mostly cloudy. High temperature around 52F. Dew point will be around 39F with an average humidity of 66%. Winds will be 6 mph from the N.

Partly cloudy. Low temperature around 39F. Dew point will be around 34F with an average humidity of 74%. Winds will be 5 mph from the N.

Partly cloudy with a slight chance of rain. Chance of precipitation 25%. High temperature around 45F. Dew point will be around 31F with an average humidity of 65%. Winds will be 5 mph from the N.

Partly cloudy with a slight chance of rain. Chance of precipitation 25%. Low temperature around 33F. Dew point will be around 27F with an average humidity of 73%. Winds will be 3 mph from the N.