Alton, IL Weather & Growing Conditions
Today
87°F
Sunny
Sunny, with a high near 87. South wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 87°F | Sunny | 6 mph S | 0% |
| Tonight | 67°F | Mostly Clear | 6 mph SE | 0% |
| Wednesday | 89°F | Sunny | 2 to 7 mph S | 12% |
| Wednesday Night | 70°F | Chance Showers And Thunderstorms | 7 mph S | 75% |
| Thursday | 85°F | Showers And Thunderstorms | 6 mph S | 75% |
| Thursday Night | 68°F | Chance Showers And Thunderstorms | 5 mph SE | 26% |
| Friday | 86°F | Chance Showers And Thunderstorms then Partly Sunny | 5 mph SW | 26% |
| Friday Night | 69°F | Chance Showers And Thunderstorms | 5 mph S | 30% |
| Saturday | 88°F | Chance Showers And Thunderstorms then Mostly Sunny | 2 to 6 mph S | 30% |
| Saturday Night | 72°F | Mostly Clear | 7 mph S | 6% |
| Sunday | 91°F | Sunny | 6 to 9 mph S | 6% |
| Sunday Night | 74°F | Mostly Clear | 8 mph S | 5% |
| Monday | 92°F | Mostly Sunny | 6 to 9 mph SW | 5% |
| Monday Night | 74°F | Slight Chance Showers And Thunderstorms | 8 mph SW | 17% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Alton, IL
Last spring frost
Apr 4
First fall frost
Nov 5
Growing season
214 days
Hardiness zone
7a
Explore more for Alton, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Alton - Melvin Price L&D, Il (5.1 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.