St. Marys, PA Weather & Growing Conditions
This Afternoon
72°F
Partly Sunny
Partly sunny, with a high near 72. South wind around 9 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| This Afternoon | 72°F | Partly Sunny | 9 mph S | 2% |
| Tonight | 57°F | Rain Showers | 9 mph S | 98% |
| Thursday | 66°F | Rain Showers Likely then Partly Sunny | 7 to 12 mph SW | 63% |
| Thursday Night | 44°F | Mostly Cloudy | 2 to 6 mph SW | 0% |
| Friday | 59°F | Mostly Cloudy then Chance Rain Showers | 2 to 7 mph SW | 34% |
| Friday Night | 35°F | Chance Rain Showers | 3 mph W | 54% |
| Saturday | 47°F | Rain Showers Likely | 5 to 10 mph W | 64% |
| Saturday Night | 31°F | Rain Showers Likely | 10 mph NW | 64% |
| Sunday | 51°F | Slight Chance Rain Showers then Partly Sunny | 12 mph W | 15% |
| Sunday Night | 30°F | Chance Rain Showers | 10 mph W | 25% |
| Monday | 51°F | Chance Rain Showers | 9 to 14 mph W | 25% |
| Monday Night | 31°F | Partly Cloudy | 7 to 10 mph W | 7% |
| Tuesday | 56°F | Mostly Sunny | 9 to 13 mph W | 8% |
| Tuesday Night | 29°F | Partly Cloudy | 2 to 7 mph W | 8% |
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 Nov 4, 2026.