10-Day Weather Forecast - O'Fallon, MO

Mostly sunny in the morning then becoming mostly cloudy. Highs in the lower 60s. Southwest winds 10 to 15 mph with gusts up to 30 mph.

Mostly cloudy. A chance of rain mainly in the evening. Lows in the mid 30s. West winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 30 percent.

Mostly cloudy in the morning then becoming partly sunny. Breezy and much cooler with highs in the lower 40s. Temperature falling into the mid 30s in the afternoon. Northwest winds 15 to 25 mph with gusts up to 35 mph.

Partly cloudy in the evening then becoming mostly clear. Much cooler with lows around 17. Northwest winds 15 to 20 mph.

Mostly sunny. Cooler with highs in the lower 30s.

Mostly cloudy. Lows in the mid 20s. Temperature rising into the lower 30s after midnight.

Partly sunny in the morning then mostly cloudy with a slight chance of rain and snow in the afternoon. Not as cool with highs in the lower 40s. Chance of precipitation 20 percent.

Mostly cloudy. Lows around 20. Highs in the upper 20s.

Mostly cloudy. Lows around 20. Highs in the upper 20s.

Partly cloudy. Lows around 10 above. Highs in the mid 20s. Wind chill values as low as 5 below.

Partly cloudy. Lows around 10 above. Highs in the mid 20s. Wind chill values as low as 5 below.

Partly cloudy in the evening then becoming mostly clear. Lows 10 to 15. Wind chill values as low as zero.

Mostly sunny. Highs in the mid 30s. Wind chill values as low as 5 above in the morning.

Clear. Low temperature around 19F. Dew point will be around 12F with an average humidity of 63%. Winds will be 4 mph from the W.

Sunny. High temperature around 34F. Dew point will be around 15F with an average humidity of 55%. Winds will be 2 mph from the SW.

Mostly clear. Low temperature around 26F. Dew point will be around 19F with an average humidity of 66%. Winds will be 4 mph from the S.

Partly cloudy. High temperature around 41F. Dew point will be around 26F with an average humidity of 66%. Winds will be 5 mph from the S.

Mostly cloudy. Low temperature around 33F. Dew point will be around 29F with an average humidity of 78%. Winds will be 4 mph from the SE.