O'Fallon, MO Weather Forecast
Local 7-day forecast
Clear
Track current conditions, temperature changes, wind, and the full daily outlook for O'Fallon, MO in one place.
Clear, with a low around 71. Northeast wind 0 to 6 mph.
Local Weather Overview
This forecast page for O'Fallon, MO is designed for quick trip planning, giving you a clean read on daytime highs, overnight lows, and changing conditions across the upcoming forecast window. Latest sync: Jul 14, 2026 8:42 PM CDT.
The active forecast window currently covers Jul 14 to Jul 21, 2026 for O'Fallon, MO.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Jul 14 to Jul 21, 2026
- Latest sync
- Jul 14, 2026 8:42 PM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in O'Fallon
Monday looks like the warmest upcoming period in O'Fallon at 94 degrees F.
Tonight is the coolest period ahead with temperatures near 71 degrees F.
The strongest winds are forecast for Saturday at about 9 mph W.
Precipitation is mentioned in 5 upcoming forecast periods.
Forecast Details
- Last updated
- Jul 14, 2026 8:42 PM CDT
- Coverage
- 8 days
- Time zone
- America/Chicago
- Forecast office
- LSX
- Radar station
- KLSX
Weather data is provided by the National Weather Service and refreshed automatically for U.S. locations.
Open NOAA sourceExtended Forecast
Isolated showers and thunderstorms between 4pm and 5pm. Sunny, with a high near 91. Northeast wind 0 to 5 mph. Chance of precipitation is 20%.
Mostly clear, with a low around 72. East wind 0 to 3 mph.
A chance of showers and thunderstorms after 1pm. Sunny, with a high near 91. Heat index values as high as 101. South wind around 2 mph. Chance of precipitation is 50%.
A chance of showers and thunderstorms before 7pm. Partly cloudy, with a low around 73. Southwest wind around 2 mph. Chance of precipitation is 50%.
A chance of showers and thunderstorms after 7am. Mostly sunny, with a high near 90. Chance of precipitation is 50%.
A chance of showers and thunderstorms before 7pm. Mostly clear, with a low around 74. Chance of precipitation is 50%.
Sunny, with a high near 93.
Mostly clear, with a low around 75.
Sunny, with a high near 93.
Mostly clear, with a low around 74.
Sunny, with a high near 94.
Mostly clear, with a low around 75.
Sunny, with a high near 91.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Tonight
Jul 14
|
Clear
|
71°F |
0 to 6 mph
NE
|
|
Wednesday
Jul 15
|
Sunny then Isolated Showers And Thunderstorms
|
91°F |
0 to 5 mph
NE
|
|
Wednesday Night
Jul 15
|
Mostly Clear
|
72°F |
0 to 3 mph
E
|
|
Thursday
Jul 16
|
Sunny then Chance Showers And Thunderstorms
|
91°F |
2 mph
S
|
|
Thursday Night
Jul 16
|
Chance Showers And Thunderstorms then Partly Cloudy
|
73°F |
2 mph
SW
|
|
Friday
Jul 17
|
Chance Showers And Thunderstorms
|
90°F |
2 to 6 mph
W
|
|
Friday Night
Jul 17
|
Chance Showers And Thunderstorms then Mostly Clear
|
74°F |
6 mph
SW
|
|
Saturday
Jul 18
|
Sunny
|
93°F |
9 mph
W
|
|
Saturday Night
Jul 18
|
Mostly Clear
|
75°F |
8 mph
W
|
|
Sunday
Jul 19
|
Sunny
|
93°F |
7 mph
W
|
|
Sunday Night
Jul 19
|
Mostly Clear
|
74°F |
6 mph
SW
|
|
Monday
Jul 20
|
Sunny
|
94°F |
8 mph
SW
|
|
Monday Night
Jul 20
|
Mostly Clear
|
75°F |
7 mph
W
|
|
Tuesday
Jul 21
|
Sunny
|
91°F |
6 to 9 mph
NW
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around O'Fallon.
