Potosi, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Potosi, a city in Washington County, Missouri.
Overnight
71°F
Partly Cloudy
Partly cloudy, with a low around 71. Southwest wind around 6 mph.
7-day forecast for Potosi
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 71°F | Partly Cloudy | 6 mph SW | 5% |
| Saturday | 98°F | Mostly Sunny | 6 mph SW | 3% |
| Saturday Night | 72°F | Partly Cloudy | 5 mph SW | 0% |
| Sunday | 95°F | Mostly Sunny | 5 mph W | 13% |
| Sunday Night | 67°F | Chance Showers And Thunderstorms | 2 mph N | 52% |
| Monday | 83°F | Showers And Thunderstorms Likely | 2 to 6 mph N | 66% |
| Monday Night | 60°F | Showers And Thunderstorms Likely | 6 mph N | 66% |
| Tuesday | 73°F | Slight Chance Rain Showers then Partly Sunny | 7 mph N | 20% |
| Tuesday Night | 54°F | Mostly Cloudy | 3 to 7 mph N | 7% |
| Wednesday | 74°F | Mostly Sunny | 6 mph N | 3% |
| Wednesday Night | 53°F | Partly Cloudy | 3 mph N | 1% |
| Thursday | 77°F | Mostly Sunny | 1 to 5 mph N | 3% |
| Thursday Night | 56°F | Partly Cloudy | 3 mph NE | 4% |
| Friday | 77°F | Mostly Sunny | 2 to 6 mph N | 8% |
Forecast source: National Weather Service (api.weather.gov) for Potosi (37.934, -90.775). Updated through the day.
Growing snapshot for Potosi
Last spring frost
Apr 11
First fall frost
Oct 28
Growing season
198 days
Hardiness zone
6b
More local growing data for Potosi: nearby ZIP 63660 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Potosi 4 Sw, Mo (7.5 mi from Potosi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.