Saint Clair County, IL Weather Forecast
County weather hub
Partly Cloudy
Compare major city weather across Saint Clair County, scan the latest forecast snapshots, and jump into local 7-day outlook pages from one hub.
Partly cloudy, with a low around 57. Northeast wind around 1 mph.
County Weather Overview
This county weather page brings together forecast coverage for Saint Clair County so visitors can compare temperatures, wind, and conditions across the region without hopping between unrelated pages.
Current forecast coverage spans 15 of 15 mapped cities in Saint Clair County.
Page Snapshot
- Page focus
- county weather
- Forecast window
- Aug 24 to Aug 30, 2026
- Latest sync
- Aug 24, 2026 5:52 AM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Saint Clair County
Sunday looks like the warmest upcoming period in Saint Clair County at 92 degrees F.
Overnight is the coolest period ahead with temperatures near 57 degrees F.
The strongest winds are forecast for Sunday at about 5 to 9 mph S.
Precipitation is mentioned in 4 upcoming forecast periods.
Forecast Details
- Last updated
- Aug 24, 2026 5:52 AM CDT
- Coverage
- 7 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
Sunny, with a high near 83. East wind 0 to 3 mph.
Mostly clear, with a low around 63. East wind around 3 mph.
Mostly sunny, with a high near 85. East wind around 5 mph.
Partly cloudy, with a low around 67. Southeast wind around 3 mph.
A slight chance of rain showers between 7am and 4pm, then a slight chance of showers and thunderstorms. Mostly sunny, with a high near 88. Chance of precipitation is 20%.
A slight chance of showers and thunderstorms before 7pm, then a chance of showers and thunderstorms between 7pm and 1am. Mostly clear, with a low around 68. Chance of precipitation is 30%.
Sunny, with a high near 87.
Mostly clear, with a low around 64.
Sunny, with a high near 87.
Mostly clear, with a low around 66.
Mostly sunny, with a high near 89.
A slight chance of showers and thunderstorms after 1am. Mostly cloudy, with a low around 70. Chance of precipitation is 20%.
A slight chance of showers and thunderstorms before 7am. Partly sunny, with a high near 92. Chance of precipitation is 20%.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Overnight
Aug 24
|
Partly Cloudy
|
57°F |
1 mph
NE
|
|
Monday
Aug 24
|
Sunny
|
83°F |
0 to 3 mph
E
|
|
Monday Night
Aug 24
|
Mostly Clear
|
63°F |
3 mph
E
|
|
Tuesday
Aug 25
|
Mostly Sunny
|
85°F |
5 mph
E
|
|
Tuesday Night
Aug 25
|
Partly Cloudy
|
67°F |
3 mph
SE
|
|
Wednesday
Aug 26
|
Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms
|
88°F |
1 to 5 mph
SW
|
|
Wednesday Night
Aug 26
|
Slight Chance Showers And Thunderstorms then Chance Showers And Thunderstorms
|
68°F |
3 mph
SW
|
|
Thursday
Aug 27
|
Sunny
|
87°F |
2 to 8 mph
NW
|
|
Thursday Night
Aug 27
|
Mostly Clear
|
64°F |
1 to 6 mph
N
|
|
Friday
Aug 28
|
Sunny
|
87°F |
0 to 3 mph
N
|
|
Friday Night
Aug 28
|
Mostly Clear
|
66°F |
3 mph
E
|
|
Saturday
Aug 29
|
Mostly Sunny
|
89°F |
2 to 6 mph
S
|
|
Saturday Night
Aug 29
|
Mostly Cloudy then Slight Chance Showers And Thunderstorms
|
70°F |
6 mph
S
|
|
Sunday
Aug 30
|
Slight Chance Showers And Thunderstorms then Partly Sunny
|
92°F |
5 to 9 mph
S
|
Major City Forecasts
Live forecast snapshots for major cities across Saint Clair County.
Coverage
Forecast coverage currently spans 15 of 15 mapped cities in Saint Clair County.
Largest mapped city population in this region: 40,536.
