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
87°F
Sunny
Sunny, with a high near 87. East southeast wind 0 to 3 mph.
7-day forecast for St. Mary
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 87°F | Sunny | 0 to 3 mph ESE | 0% |
| Tonight | 65°F | Mostly Clear | 3 mph SE | 0% |
| Wednesday | 90°F | Sunny | 1 to 5 mph S | 2% |
| Wednesday Night | 70°F | Partly Cloudy then Chance Showers And Thunderstorms | 6 mph SSE | 32% |
| Thursday | 89°F | Chance Showers And Thunderstorms | 5 mph S | 50% |
| Thursday Night | 70°F | Chance Showers And Thunderstorms | 5 mph SSE | 59% |
| Friday | 88°F | Showers And Thunderstorms Likely then Chance Showers And Thunderstorms | 3 mph SSW | 59% |
| Friday Night | 70°F | Chance Showers And Thunderstorms | 2 mph SSW | 37% |
| Saturday | 89°F | Chance Showers And Thunderstorms | 3 mph SSW | 37% |
| Saturday Night | 70°F | Partly Cloudy | 5 mph S | 14% |
| Sunday | 92°F | Sunny | 7 mph SSW | 8% |
| Sunday Night | 72°F | Mostly Clear | 7 mph S | 4% |
| Monday | 94°F | Sunny | 5 to 8 mph SSW | 4% |
| Monday Night | 73°F | Mostly Clear | 8 mph SSW | 7% |
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 Aug 4, 2026.