Potosi, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Potosi, a city in Washington County, Missouri.
Overnight
50°F
Slight Chance Light Rain
A slight chance of rain before 1am, then a slight chance of drizzle between 1am and 4am. Mostly cloudy, with a low around 50. Southwest wind around 8 mph, with gusts as high as 21 mph. Chance of precipitation is 20%.
7-day forecast for Potosi
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 50°F | Slight Chance Light Rain | 8 mph SW | 18% |
| Wednesday | 63°F | Mostly Cloudy | 6 to 9 mph W | 2% |
| Wednesday Night | 41°F | Mostly Clear | 5 mph W | 0% |
| Thursday | 66°F | Sunny | 7 mph W | 3% |
| Thursday Night | 41°F | Slight Chance T-storms then Mostly Cloudy | 3 mph NW | 15% |
| Friday | 58°F | Partly Sunny | 3 to 7 mph NW | 4% |
| Friday Night | 37°F | Mostly Cloudy | 1 to 5 mph N | 3% |
| Saturday | 57°F | Partly Sunny | 3 mph NW | 0% |
| Saturday Night | 34°F | Partly Cloudy | 1 mph NW | 2% |
| Sunday | 63°F | Sunny | 1 to 5 mph W | 7% |
| Sunday Night | 34°F | Mostly Clear | 3 mph W | 5% |
| Monday | 67°F | Sunny | 2 to 6 mph SW | 2% |
| Monday Night | 39°F | Mostly Clear | 3 mph SW | 1% |
| Tuesday | 70°F | Sunny | 5 mph W | 1% |
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 Nov 4, 2026.