St. Mary, MO Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Mary, a city in Ste. Genevieve County, Missouri.
Today
63°F
Slight Chance Drizzle then Partly Sunny
A slight chance of drizzle between 7am and noon. Partly sunny, with a high near 63. West wind 6 to 10 mph.
7-day forecast for St. Mary
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 63°F | Slight Chance Drizzle then Partly Sunny | 6 to 10 mph W | 12% |
| Tonight | 40°F | Mostly Clear | 3 mph WSW | 0% |
| Thursday | 70°F | Sunny | 3 to 7 mph WSW | 0% |
| Thursday Night | 43°F | Partly Cloudy | 3 mph NW | 1% |
| Friday | 60°F | Partly Sunny | 5 to 10 mph NNW | 1% |
| Friday Night | 34°F | Partly Cloudy | 2 to 7 mph N | 0% |
| Saturday | 57°F | Mostly Sunny | 5 mph N | 0% |
| Saturday Night | 31°F | Partly Cloudy | 1 mph NW | 0% |
| Sunday | 63°F | Sunny | 1 to 6 mph NW | 1% |
| Sunday Night | 33°F | Clear | 1 mph WNW | 0% |
| Monday | 67°F | Sunny | 0 to 3 mph WSW | 0% |
| Monday Night | 37°F | Clear | 2 mph SW | 0% |
| Tuesday | 71°F | Sunny | 3 mph W | 1% |
| Tuesday Night | 40°F | Mostly Clear | 2 mph WNW | 2% |
Forecast source: National Weather Service (api.weather.gov) for St. Mary (37.874, -89.950). Updated through the day.
Growing snapshot for St. Mary
Last spring frost
Apr 19
First fall frost
Oct 20
Growing season
182 days
Hardiness zone
6b
More local growing data for St. Mary: nearby ZIP 63673 weather · frost dates · planting calendar · Missouri frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Perryville Wtp, Mo (8.4 mi from St. Mary). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.