Williamstown, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamstown, a community in Lewis County, Missouri.
This Afternoon
90°F
Mostly Cloudy
Mostly cloudy, with a high near 90. Southwest wind around 7 mph.
7-day forecast for Williamstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 90°F | Mostly Cloudy | 7 mph SW | 2% |
| Tonight | 68°F | Mostly Cloudy then Chance Showers And Thunderstorms | 3 mph W | 52% |
| Sunday | 77°F | Chance Showers And Thunderstorms | 2 to 8 mph N | 69% |
| Sunday Night | 61°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 9 mph NE | 71% |
| Monday | 66°F | Showers And Thunderstorms | 8 mph NE | 79% |
| Monday Night | 56°F | Rain Showers Likely | 7 mph NE | 62% |
| Tuesday | 64°F | Chance Rain Showers | 8 mph NE | 31% |
| Tuesday Night | 50°F | Mostly Cloudy | 3 to 7 mph N | 6% |
| Wednesday | 66°F | Mostly Sunny | 6 mph N | 0% |
| Wednesday Night | 53°F | Partly Cloudy | 3 mph NE | 1% |
| Thursday | 70°F | Partly Sunny | 3 mph NE | 3% |
| Thursday Night | 58°F | Slight Chance Rain Showers | 2 mph NE | 18% |
| Friday | 74°F | Slight Chance Rain Showers | 1 to 5 mph NE | 18% |
| Friday Night | 59°F | Mostly Cloudy | 3 mph NE | 9% |
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 Sep 19, 2026.