Alton, IL Weather & Growing Conditions
Tonight
56°F
Rain
Rain and a slight chance of thunderstorms before 3am, then a chance of rain showers. Cloudy, with a low around 56. Southwest wind 9 to 17 mph, with gusts as high as 30 mph. Chance of precipitation is 80%.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 56°F | Rain | 9 to 17 mph SW | 83% |
| Wednesday | 63°F | Chance Rain Showers then Mostly Cloudy | 9 to 15 mph W | 12% |
| Wednesday Night | 42°F | Partly Cloudy | 5 to 8 mph SW | 0% |
| Thursday | 65°F | Sunny | 6 to 13 mph W | 2% |
| Thursday Night | 42°F | Mostly Cloudy | 6 mph NW | 10% |
| Friday | 58°F | Mostly Cloudy | 6 to 12 mph NW | 5% |
| Friday Night | 37°F | Partly Cloudy | 2 to 8 mph N | 1% |
| Saturday | 56°F | Mostly Sunny | 5 mph NW | 0% |
| Saturday Night | 35°F | Partly Cloudy | 2 mph NW | 1% |
| Sunday | 62°F | Sunny | 2 to 8 mph W | 7% |
| Sunday Night | 35°F | Mostly Clear | 2 to 6 mph W | 4% |
| Monday | 66°F | Sunny | 2 to 8 mph SW | 2% |
| Monday Night | 39°F | Mostly Clear | 6 mph SW | 1% |
| Tuesday | 68°F | Sunny | 3 to 7 mph W | 0% |
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 Nov 4, 2026.