Saint Clair County, IL Weather Forecast
County weather hub
Sunny
Compare major city weather across Saint Clair County, scan the latest forecast snapshots, and jump into local 7-day outlook pages from one hub.
Sunny, with a high near 95. Heat index values as high as 102. Southwest wind 6 to 9 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
- Oct 13 to Oct 18, 2026
- Latest sync
- Oct 12, 2026 2:08 PM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Saint Clair County
Tuesday looks like the warmest upcoming period in Saint Clair County at 95 degrees F.
Saturday Night is the coolest period ahead with temperatures near 37 degrees F.
The strongest winds are forecast for Friday at about 18 to 22 mph NW.
Precipitation is mentioned in 6 upcoming forecast periods.
Forecast Details
- Last updated
- Oct 12, 2026 2:08 PM CDT
- Coverage
- 6 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
A slight chance of showers and thunderstorms between 1am and 3am, then a chance of showers and thunderstorms. Partly cloudy, with a low around 71. Southwest wind 5 to 8 mph. Chance of precipitation is 50%.
Showers and thunderstorms. Mostly cloudy, with a high near 82. West wind around 5 mph. Chance of precipitation is 100%.
Showers and thunderstorms. Mostly cloudy, with a low around 67. Chance of precipitation is 90%.
Showers and thunderstorms. Partly sunny, with a high near 83. Chance of precipitation is 80%.
Showers and thunderstorms likely. Mostly cloudy, with a low around 54. Chance of precipitation is 70%.
A chance of showers and thunderstorms before 7am. Mostly sunny, with a high near 64. Chance of precipitation is 30%.
Mostly clear, with a low around 39.
Sunny, with a high near 62.
Clear, with a low around 37.
Sunny, with a high near 70.
Mostly clear, with a low around 45.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Tuesday
Oct 13
|
Sunny
|
95°F |
6 to 9 mph
SW
|
|
Tuesday Night
Oct 13
|
Partly Cloudy then Slight Chance Showers And Thunderstorms
|
71°F |
5 to 8 mph
SW
|
|
Wednesday
Oct 14
|
Showers And Thunderstorms
|
82°F |
5 mph
W
|
|
Wednesday Night
Oct 14
|
Showers And Thunderstorms
|
67°F |
2 mph
NE
|
|
Thursday
Oct 15
|
Showers And Thunderstorms
|
83°F |
3 to 7 mph
S
|
|
Thursday Night
Oct 15
|
Showers And Thunderstorms Likely
|
54°F |
6 to 17 mph
NW
|
|
Friday
Oct 16
|
Chance Showers And Thunderstorms then Mostly Sunny
|
64°F |
18 to 22 mph
NW
|
|
Friday Night
Oct 16
|
Mostly Clear
|
39°F |
6 to 18 mph
N
|
|
Saturday
Oct 17
|
Sunny
|
62°F |
6 mph
NE
|
|
Saturday Night
Oct 17
|
Clear
|
37°F |
3 mph
E
|
|
Sunday
Oct 18
|
Sunny
|
70°F |
2 to 8 mph
S
|
|
Sunday Night
Oct 18
|
Mostly Clear
|
45°F |
2 to 6 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.
