Collinsville, IL Weather Forecast
Local 7-day forecast
Patchy Fog then Mostly Sunny
Track current conditions, temperature changes, wind, and the full daily outlook for Collinsville, IL in one place.
Patchy fog before 9am. Mostly sunny, with a high near 84. Southeast wind 1 to 5 mph.
Local Weather Overview
This forecast page for Collinsville, IL 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: Aug 23, 2026 7:52 PM CDT.
The active forecast window currently covers Aug 24 to Aug 29, 2026 for Collinsville, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- Aug 24 to Aug 29, 2026
- Latest sync
- Aug 23, 2026 7:52 PM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Collinsville
Wednesday looks like the warmest upcoming period in Collinsville at 90 degrees F.
Monday Night is the coolest period ahead with temperatures near 61 degrees F.
The strongest winds are forecast for Thursday at about 2 to 9 mph NW.
Precipitation is mentioned in 3 upcoming forecast periods.
Forecast Details
- Last updated
- Aug 23, 2026 7:52 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
Mostly clear, with a low around 61. East wind around 5 mph.
Mostly sunny, with a high near 86. East wind around 6 mph.
Partly cloudy, with a low around 67.
Mostly sunny, with a high near 90.
A slight chance of showers and thunderstorms between 7pm and 1am. Partly cloudy, with a low around 68. Chance of precipitation is 20%.
Sunny, with a high near 88.
Mostly clear, with a low around 66.
Sunny, with a high near 87.
Partly cloudy, with a low around 67.
A slight chance of rain showers between 7am and 1pm. Mostly sunny, with a high near 88. Chance of precipitation is 20%.
A chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 71. Chance of precipitation is 30%.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Monday
Aug 24
|
Patchy Fog then Mostly Sunny
|
84°F |
1 to 5 mph
SE
|
|
Monday Night
Aug 24
|
Mostly Clear
|
61°F |
5 mph
E
|
|
Tuesday
Aug 25
|
Mostly Sunny
|
86°F |
6 mph
E
|
|
Tuesday Night
Aug 25
|
Partly Cloudy
|
67°F |
5 mph
SE
|
|
Wednesday
Aug 26
|
Mostly Sunny
|
90°F |
2 to 6 mph
S
|
|
Wednesday Night
Aug 26
|
Slight Chance Showers And Thunderstorms
|
68°F |
5 mph
W
|
|
Thursday
Aug 27
|
Sunny
|
88°F |
2 to 9 mph
NW
|
|
Thursday Night
Aug 27
|
Mostly Clear
|
66°F |
1 to 8 mph
N
|
|
Friday
Aug 28
|
Sunny
|
87°F |
0 to 5 mph
N
|
|
Friday Night
Aug 28
|
Partly Cloudy
|
67°F |
5 mph
E
|
|
Saturday
Aug 29
|
Slight Chance Rain Showers
|
88°F |
3 to 8 mph
SE
|
|
Saturday Night
Aug 29
|
Partly Cloudy then Chance Showers And Thunderstorms
|
71°F |
8 mph
S
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Collinsville.
