Williamstown, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamstown, a community in Lewis County, Missouri.
Today
90°F
Mostly Cloudy
Mostly cloudy, with a high near 90. Southwest wind around 8 mph.
7-day forecast for Williamstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 90°F | Mostly Cloudy | 8 mph SW | 6% |
| Tonight | 68°F | Chance Showers And Thunderstorms | 3 mph NW | 58% |
| Sunday | 77°F | Chance Showers And Thunderstorms | 2 to 9 mph N | 54% |
| Sunday Night | 61°F | Chance Showers And Thunderstorms then Showers And Thunderstorms Likely | 9 mph NE | 68% |
| Monday | 66°F | Showers And Thunderstorms Likely | 10 mph NE | 68% |
| Monday Night | 55°F | Chance Rain Showers | 9 mph NE | 32% |
| Tuesday | 63°F | Chance Rain Showers then Partly Sunny | 9 mph NE | 32% |
| Tuesday Night | 50°F | Partly Cloudy | 3 to 7 mph NE | 4% |
| Wednesday | 67°F | Mostly Sunny | 6 mph NE | 1% |
| Wednesday Night | 53°F | Partly Cloudy | 3 mph NE | 2% |
| Thursday | 71°F | Partly Sunny | 5 mph NE | 5% |
| Thursday Night | 56°F | Mostly Cloudy | 3 mph NE | 4% |
| Friday | 73°F | Partly Sunny | 5 mph E | 8% |
| Friday Night | 57°F | Mostly Cloudy | 3 mph E | 6% |
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.