Alton, IL Weather Forecast
Local 7-day forecast
Sunny
Track current conditions, temperature changes, wind, and the full daily outlook for Alton, IL in one place.
Sunny, with a high near 83. East wind 2 to 9 mph.
Local Weather Overview
This forecast page for Alton, 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: May 24, 2026 12:56 PM CDT.
The active forecast window currently covers May 25 to May 30, 2026 for Alton, IL.
Page Snapshot
- Page focus
- city weather
- Forecast window
- May 25 to May 30, 2026
- Latest sync
- May 24, 2026 12:56 PM CDT
- Forecast office
- LSX
- Source
- NOAA / NWS
Daily Outlook
This Week in Alton
Wednesday looks like the warmest upcoming period in Alton at 85 degrees F.
Saturday Night is the coolest period ahead with temperatures near 59 degrees F.
The strongest winds are forecast for Friday at about 5 to 12 mph NE.
Precipitation is mentioned in 10 upcoming forecast periods.
Forecast Details
- Last updated
- May 24, 2026 12:56 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
Partly cloudy, with a low around 62. East wind 2 to 8 mph.
A slight chance of rain showers between 7am and 10am, then a chance of showers and thunderstorms. Mostly cloudy, with a high near 82. East wind 3 to 8 mph. Chance of precipitation is 50%.
A chance of showers and thunderstorms before 10pm, then a chance of showers and thunderstorms. Mostly cloudy, with a low around 65. Chance of precipitation is 50%.
A chance of showers and thunderstorms before 7am, then a chance of showers and thunderstorms. Partly sunny, with a high near 85. Chance of precipitation is 50%.
A chance of showers and thunderstorms. Partly cloudy, with a low around 66. Chance of precipitation is 50%.
A slight chance of rain showers before 7am, then a chance of showers and thunderstorms. Partly sunny, with a high near 85. Chance of precipitation is 40%.
A chance of showers and thunderstorms before 7pm, then showers and thunderstorms likely. Mostly cloudy, with a low around 65. Chance of precipitation is 60%.
A chance of showers and thunderstorms before 1pm, then a chance of showers and thunderstorms. Partly sunny, with a high near 80. Chance of precipitation is 50%.
A chance of showers and thunderstorms before 7pm, then a chance of showers and thunderstorms. Mostly cloudy, with a low around 60. Chance of precipitation is 50%.
A slight chance of rain showers before 1pm, then a chance of showers and thunderstorms. Mostly sunny, with a high near 79. Chance of precipitation is 30%.
A chance of showers and thunderstorms before 7pm. Partly cloudy, with a low around 59. Chance of precipitation is 30%.
Detailed Forecast
| Period | Conditions | Temp | Wind |
|---|---|---|---|
|
Memorial Day
May 25
|
Sunny
|
83°F |
2 to 9 mph
E
|
|
Monday Night
May 25
|
Partly Cloudy
|
62°F |
2 to 8 mph
E
|
|
Tuesday
May 26
|
Chance Showers And Thunderstorms
|
82°F |
3 to 8 mph
E
|
|
Tuesday Night
May 26
|
Chance Showers And Thunderstorms
|
65°F |
3 to 7 mph
SE
|
|
Wednesday
May 27
|
Chance Showers And Thunderstorms
|
85°F |
6 mph
SE
|
|
Wednesday Night
May 27
|
Chance Showers And Thunderstorms
|
66°F |
1 to 5 mph
E
|
|
Thursday
May 28
|
Slight Chance Rain Showers then Chance Showers And Thunderstorms
|
85°F |
2 to 7 mph
E
|
|
Thursday Night
May 28
|
Chance Showers And Thunderstorms then Showers And Thunderstorms Likely
|
65°F |
6 mph
E
|
|
Friday
May 29
|
Chance Showers And Thunderstorms
|
80°F |
5 to 12 mph
NE
|
|
Friday Night
May 29
|
Chance Showers And Thunderstorms
|
60°F |
7 to 10 mph
NE
|
|
Saturday
May 30
|
Chance Showers And Thunderstorms
|
79°F |
7 to 12 mph
NE
|
|
Saturday Night
May 30
|
Chance Showers And Thunderstorms then Partly Cloudy
|
59°F |
5 to 10 mph
NE
|
Nearby Forecasts
Explore weather pages for nearby cities and major places around Alton.
