St. Marys, PA Weather & Growing Conditions
This Afternoon
74°F
Mostly Sunny
Mostly sunny, with a high near 74. North wind around 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 74°F | Mostly Sunny | 6 mph N | 0% |
| Tonight | 48°F | Partly Cloudy then Patchy Fog | 2 to 6 mph NE | 1% |
| Saturday | 70°F | Patchy Fog then Partly Sunny | 5 mph SE | 4% |
| Saturday Night | 57°F | Showers And Thunderstorms | 6 mph SE | 85% |
| Sunday | 70°F | Showers And Thunderstorms | 6 mph SW | 94% |
| Sunday Night | 49°F | Rain Showers Likely | 8 mph N | 60% |
| Monday | 64°F | Chance Rain Showers | 9 mph NE | 27% |
| Monday Night | 47°F | Chance Rain Showers | 9 mph E | 54% |
| Tuesday | 60°F | Rain Showers Likely | 10 mph E | 58% |
| Tuesday Night | 45°F | Rain Showers Likely | 10 to 14 mph E | 56% |
| Wednesday | 57°F | Rain Showers Likely | 12 mph E | 56% |
| Wednesday Night | 45°F | Chance Showers And Thunderstorms | 7 to 10 mph E | 54% |
| Thursday | 60°F | Chance Showers And Thunderstorms | 8 mph E | 54% |
| Thursday Night | 46°F | Chance Rain Showers | 2 to 7 mph NE | 41% |
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 (8.4 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.