Williamson, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamson, a village in Madison County, Illinois.
Today
86°F
Sunny
Sunny, with a high near 86. South wind around 3 mph.
7-day forecast for Williamson
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 86°F | Sunny | 3 mph S | 0% |
| Tonight | 65°F | Mostly Clear | 3 mph SE | 0% |
| Wednesday | 88°F | Sunny | 1 to 6 mph S | 12% |
| Wednesday Night | 69°F | Slight Chance Showers And Thunderstorms | 6 mph S | 70% |
| Thursday | 84°F | Showers And Thunderstorms | 6 mph S | 75% |
| Thursday Night | 67°F | Chance Showers And Thunderstorms | 3 mph SE | 29% |
| Friday | 85°F | Chance Showers And Thunderstorms then Partly Sunny | 3 mph SW | 29% |
| Friday Night | 68°F | Chance Showers And Thunderstorms | 2 mph S | 32% |
| Saturday | 87°F | Chance Showers And Thunderstorms then Mostly Sunny | 1 to 5 mph S | 32% |
| Saturday Night | 70°F | Mostly Clear | 6 mph S | 9% |
| Sunday | 89°F | Sunny | 5 to 9 mph S | 7% |
| Sunday Night | 72°F | Mostly Clear | 8 mph S | 5% |
| Monday | 91°F | Mostly Sunny | 6 to 9 mph S | 6% |
| Monday Night | 73°F | Slight Chance Showers And Thunderstorms | 9 mph S | 15% |
Forecast source: National Weather Service (api.weather.gov) for Williamson (38.985, -89.763). Updated through the day.
Growing snapshot for Williamson
Last spring frost
Apr 13
First fall frost
Oct 24
Growing season
192 days
Hardiness zone
6b
More local growing data for Williamson: nearby ZIP 62058 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Alhambra
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Bethalto
Collinsville
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Godfrey
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Hamel
Hartford
Highland
Holiday Shores
Livingston
Madison
Marine
Maryville
Mitchell
Moro
New Douglas
Pontoon Beach
Prairietown
Rosewood Heights
Roxana
South Roxana
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Venice
Wood River
Climate data from the nearest NOAA station, Hillsboro, Il (19.8 mi from Williamson). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.