| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
||||||||||||||||||||||||||||||||||||||||||||||||
| Updated: Wednesday, 12-Aug-2026 05:00 am | ||||||||||||||||||||||||||||||||||||||||||||||||
|
| Today |
Mostly sunny in the morning, becoming partly cloudy in the afternoon. A chance of rain. Scattered thunderstorms likely. Very hot. High 101°. Heat index up to 111°. UV index up to 9. Wind southwest around 7 mph, gusting to 27 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Tonight |
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. Patchy light fog after midnight. A slight chance of rain in the evening, then a chance of rain after midnight. Scattered thundershowers possible. Warm. Low 78°. Wind south around 3 mph, gusting to 17 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch. |
| Thursday |
Partly cloudy in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. A chance of rain in the morning, then a slight chance of rain in the afternoon. Scattered thunderstorms likely. Very hot. High 95°. Heat index up to 109°. UV index up to 9. Wind south around 5 mph, gusting to 21 mph. Chance of precipitation 40 percent. Precipitation mostly less than a tenth of an inch. |
| Thursday night |
Partly cloudy in the evening, becoming fair to partly cloudy after midnight. Patchy light fog in the evening, then moderate fog after midnight. A chance of rain. Scattered thundershowers possible. Warm. Low 77°. Wind south around 5 mph, gusting to 16 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Friday |
Partly to mostly sunny in the morning, becoming mostly sunny in the afternoon. Very hot. High 99°. Heat index up to 112°. UV index up to 8. Wind south-southwest around 6 mph, gusting to 23 mph. |
| Friday night |
Fair in the evening, becoming fair to partly cloudy after midnight. Low 76°. Wind south around 2 mph. |
| Saturday |
Partly to mostly sunny in the morning, becoming sunny in the afternoon. Very hot. High 99°. Heat index up to 111°. UV index up to 8. Wind southwest around 5 mph, gusting to 22 mph. |
| Saturday night |
Fair to partly cloudy in the evening, becoming clear after midnight. Low 74°. Wind south around 3 mph, gusting to 15 mph. |
| Sunday |
Sunny. Near record heat. High 103°. Heat index up to 110°. UV index up to 9. Wind west-southwest around 6 mph, gusting to 25 mph. |
| Sunday night |
Partly cloudy in the evening, becoming partly to mostly cloudy after midnight. A chance of rain. Scattered thundershowers possible. Low 74°. Wind northwest around 4 mph, gusting to 17 mph. Chance of precipitation 30 percent. Precipitation mostly less than a tenth of an inch. |
| Monday |
Partly to mostly cloudy. A slight chance of rain in the morning, then a chance of rain in the afternoon. Precipitation showery or intermittent. Hot. High 92°. Heat index up to 98°. UV index up to 7. Wind north-northwest around 5 mph, gusting to 25 mph. Chance of precipitation 50 percent. Precipitation mostly less than a quarter of an inch. |
| Monday night |
Fair in the evening, becoming fair to partly cloudy after midnight. Moderate fog. A chance of rain. Low 70°. Wind northeast around 4 mph, gusting to 15 mph. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch. |
| Tuesday |
Sunny in the morning, becoming partly to mostly sunny in the afternoon. Moderate fog in the morning. Hot. High 90°. Heat index up to 97°. UV index up to 7. Wind east-southeast around 3 mph, gusting to 20 mph. |
| Tuesday night |
Clear in the evening, becoming fair after midnight. Patchy light fog after midnight. Low 69°. Wind east-southeast around 5 mph, gusting to 17 mph. |
WXSIM forecast formatting script by Saratoga-Weather.org.
Powered by Davis Vantage Pro2
and
CumulusMX
v 4.6.4 (b4128)
MXUI Template v 2.2.6 by
Silver Acorn
Valid HTML5