St. Marys, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Marys, a city in Elk County, Pennsylvania.
Today
70°F
Partly Sunny
Partly sunny, with a high near 70. Southeast wind around 6 mph.
7-day forecast for St. Marys
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 70°F | Partly Sunny | 6 mph SE | 1% |
| Tonight | 56°F | Rain Showers | 7 mph SE | 86% |
| Sunday | 69°F | Rain Showers | 8 mph SW | 86% |
| Sunday Night | 45°F | Chance Rain Showers then Mostly Cloudy | 6 to 9 mph NE | 31% |
| Monday | 64°F | Mostly Cloudy | 9 mph NE | 4% |
| Monday Night | 43°F | Chance Rain Showers | 8 mph E | 48% |
| Tuesday | 59°F | Chance Rain Showers | 10 mph E | 49% |
| Tuesday Night | 42°F | Chance Rain Showers | 13 mph E | 47% |
| Wednesday | 56°F | Chance Rain Showers | 13 mph E | 47% |
| Wednesday Night | 42°F | Chance Rain Showers | 7 to 10 mph E | 45% |
| Thursday | 60°F | Chance Rain Showers | 8 mph E | 45% |
| Thursday Night | 42°F | Chance Showers And Thunderstorms | 3 to 7 mph E | 30% |
| Friday | 65°F | Slight Chance Rain Showers | 5 to 8 mph NE | 19% |
| Friday Night | 43°F | Slight Chance Rain Showers then Mostly Cloudy | 3 to 8 mph NE | 19% |
Forecast source: National Weather Service (api.weather.gov) for St. Marys (41.455, -78.520). Updated through the day.
Growing snapshot for St. Marys
Last spring frost
May 14
First fall frost
Oct 6
Growing season
143 days
Hardiness zone
5b
More local growing data for St. Marys: nearby ZIP 15857 weather · frost dates · planting calendar · Pennsylvania frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Glen Hazel 2 Ne Dam, Pa (8.4 mi from St. Marys). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.