Williamstown, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamstown, a community in Lewis County, Missouri.
Today
89°F
Sunny
Sunny, with a high near 89. South wind around 7 mph.
7-day forecast for Williamstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 89°F | Sunny | 7 mph S | 1% |
| Tonight | 69°F | Isolated Rain Showers then Isolated Showers And Thunderstorms | 5 mph SE | 19% |
| Wednesday | 84°F | Chance Showers And Thunderstorms | 3 mph S | 72% |
| Wednesday Night | 66°F | Showers And Thunderstorms then Showers And Thunderstorms Likely | 5 mph NE | 78% |
| Thursday | 83°F | Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 3 mph NE | 78% |
| Thursday Night | 65°F | Mostly Clear | 2 mph SE | 5% |
| Friday | 86°F | Mostly Sunny | 2 mph S | 7% |
| Friday Night | 68°F | Slight Chance Showers And Thunderstorms | 2 mph S | 22% |
| Saturday | 89°F | Slight Chance Showers And Thunderstorms then Sunny | 2 to 6 mph SW | 21% |
| Saturday Night | 72°F | Mostly Clear | 7 mph S | 7% |
| Sunday | 92°F | Sunny | 6 to 10 mph SW | 7% |
| Sunday Night | 72°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 5 to 9 mph S | 15% |
| Monday | 92°F | Slight Chance Showers And Thunderstorms then Mostly Sunny | 7 to 12 mph SW | 15% |
| Monday Night | 73°F | Partly Cloudy then Slight Chance Showers And Thunderstorms | 9 mph SW | 23% |
Forecast source: National Weather Service (api.weather.gov) for Williamstown (40.241, -91.798). Updated through the day.
Growing snapshot for Williamstown
Last spring frost
Apr 11
First fall frost
Oct 23
Growing season
194 days
Hardiness zone
6a
More local growing data for Williamstown: nearby ZIP 63473 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Canton L&D 20, Mo (15.3 mi from Williamstown). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.