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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

WhenTempForecastWindPrecip
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

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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.