| WXSIM Forecast for:
O'Fallon Issued by: OFallonweather.com |
||||||||||||||||||||||||||||||||||||||||||||||||
| Updated: Sunday, 30-Aug-2026 04:00 pm | ||||||||||||||||||||||||||||||||||||||||||||||||
|
| Tonight |
Clear in the evening, becoming fair after midnight. Low 70°. Wind south around 7 mph, gusting to 23 mph. |
| Monday |
Sunny. Very hot. High 96°. Heat index up to 102°. UV index up to 8. Wind south-southwest around 7 mph, gusting to 23 mph. |
| Monday night |
Clear. Low 70°. Wind south around 5 mph. |
| Tuesday |
Sunny. Very hot. High 97°. Heat index up to 103°. UV index up to 8. Wind southwest around 6 mph, gusting to 21 mph. |
| Tuesday night |
Clear. Patchy light fog after midnight. Low 70°. Wind south around 5 mph. |
| Wednesday |
Sunny. Patchy light fog in the morning. Very hot. High 98°. Heat index up to 105°. UV index up to 8. Wind southwest around 6 mph, gusting to 22 mph. |
| Wednesday night |
Clear. Patchy light fog after midnight. Low 71°. Wind south around 5 mph. |
| Thursday |
Sunny. Patchy light fog in the morning. Very hot. High 97°. Heat index up to 106°. UV index up to 8. Wind southwest around 5 mph, gusting to 19 mph. |
| Thursday night |
Clear. Patchy light fog after midnight. Low 71°. Wind south around 4 mph. |
| Friday |
Sunny in the morning, becoming partly to mostly sunny in the afternoon. Patchy light fog in the morning. Very hot. High 99°. Heat index up to 108°. UV index up to 8. Wind southwest around 5 mph, gusting to 21 mph, in the morning, becoming north in the afternoon. |
| Friday night |
Mostly clear in the evening, becoming fair to partly cloudy after midnight. Patchy light fog after midnight. Low 72°. Wind south-southeast around 3 mph. |
| Saturday |
Partly cloudy in the morning, becoming partly to mostly cloudy in the afternoon. Patchy light fog in the morning. A slight chance of rain in the morning, then a chance of rain in the afternoon. Scattered thundershowers possible. Very hot. High 93°. Heat index up to 101°. UV index up to 6. Wind southwest around 4 mph, gusting to 19 mph, in the morning, becoming east in the afternoon. Chance of precipitation 40 percent. Precipitation mostly around a tenth of an inch. |
| Saturday night |
Mostly clear in the evening, becoming fair after midnight. Patchy light fog. Low 71°. Wind south-southwest around 2 mph in the evening, becoming southeast after midnight. |
WXSIM forecast formatting script by Saratoga-Weather.org.