Williamstown, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Williamstown, a community in Lewis County, Missouri.
Tonight
50°F
Chance Rain Showers
A chance of rain showers. Cloudy, with a low around 50. Southwest wind around 12 mph, with gusts as high as 22 mph.
7-day forecast for Williamstown
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 50°F | Chance Rain Showers | 12 mph SW | 12% |
| Wednesday | 56°F | Chance Rain Showers then Cloudy | 13 mph W | 12% |
| Wednesday Night | 44°F | Mostly Cloudy | 9 mph SW | 1% |
| Thursday | 57°F | Partly Sunny | 7 to 10 mph W | 14% |
| Thursday Night | 43°F | Mostly Cloudy then Slight Chance T-storms | 7 mph NW | 24% |
| Friday | 54°F | Mostly Cloudy | 8 mph N | 3% |
| Friday Night | 36°F | Mostly Cloudy | 1 to 5 mph N | 0% |
| Saturday | 55°F | Partly Sunny | 1 to 5 mph W | 1% |
| Saturday Night | 37°F | Mostly Clear | 3 mph W | 4% |
| Sunday | 61°F | Sunny | 3 to 7 mph W | 10% |
| Sunday Night | 37°F | Mostly Clear | 3 mph W | 2% |
| Monday | 65°F | Sunny | 3 to 9 mph SW | 2% |
| Monday Night | 42°F | Mostly Clear | 6 mph W | 0% |
| Tuesday | 66°F | Sunny | 6 mph NW | 0% |
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 Nov 4, 2026.