St. Marys, PA Weather & Growing Conditions
Tonight
47°F
Partly Cloudy then Areas Of Fog
Areas of fog after midnight. Partly cloudy, with a low around 47. Northeast wind 2 to 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 47°F | Partly Cloudy then Areas Of Fog | 2 to 6 mph NE | 1% |
| Saturday | 68°F | Patchy Fog then Partly Sunny | 5 mph SE | 4% |
| Saturday Night | 55°F | Showers And Thunderstorms | 6 mph SE | 88% |
| Sunday | 68°F | Showers And Thunderstorms | 6 mph SW | 93% |
| Sunday Night | 48°F | Rain Showers Likely | 8 mph N | 57% |
| Monday | 63°F | Chance Rain Showers | 9 mph NE | 26% |
| Monday Night | 46°F | Chance Rain Showers | 9 mph E | 53% |
| Tuesday | 59°F | Chance Rain Showers | 10 mph E | 53% |
| Tuesday Night | 43°F | Rain Showers Likely | 12 to 15 mph E | 55% |
| Wednesday | 56°F | Rain Showers Likely | 12 mph E | 55% |
| Wednesday Night | 44°F | Chance Showers And Thunderstorms | 7 to 10 mph E | 54% |
| Thursday | 59°F | Chance Showers And Thunderstorms | 8 mph E | 54% |
| Thursday Night | 45°F | Chance Rain Showers | 2 to 6 mph NE | 41% |
| Friday | 65°F | Partly Sunny | 3 to 7 mph N | 14% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for St. Marys, PA
Last spring frost
May 14
First fall frost
Oct 6
Growing season
143 days
Hardiness zone
5b
Explore more for St. Marys, PA: full frost dates · planting calendar · Pennsylvania frost dates
Climate data from the nearest NOAA station, Glen Hazel 2 Ne Dam, Pa (1.8 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.