St. Clair, PA Weather & Growing Conditions
Today
73°F
Patchy Fog then Mostly Sunny
Patchy fog before 9am. Mostly sunny, with a high near 73. South wind 0 to 6 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 73°F | Patchy Fog then Mostly Sunny | 0 to 6 mph S | 1% |
| Tonight | 57°F | Mostly Cloudy then Chance Light Rain | 5 mph SE | 46% |
| Thursday | 70°F | Light Rain | 6 mph S | 96% |
| Thursday Night | 55°F | Chance Light Rain | 2 mph W | 52% |
| Friday | 68°F | Chance Light Rain | 1 mph NW | 25% |
| Friday Night | 46°F | Chance Light Rain then Partly Cloudy | 1 mph NW | 25% |
| Saturday | 59°F | Mostly Sunny then Slight Chance Light Rain | 2 to 7 mph NW | 21% |
| Saturday Night | 40°F | Slight Chance Light Rain | 7 mph NW | 21% |
| Sunday | 57°F | Mostly Sunny | 5 to 8 mph NW | 6% |
| Sunday Night | 36°F | Mostly Clear | 5 mph W | 4% |
| Monday | 57°F | Mostly Sunny | 5 to 9 mph NW | 8% |
| Monday Night | 35°F | Mostly Clear | 2 to 6 mph W | 6% |
| Tuesday | 61°F | Mostly Sunny | 3 to 8 mph W | 5% |
| Tuesday Night | 35°F | Mostly Clear | 2 to 6 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for St. Clair, PA
Last spring frost
Apr 30
First fall frost
Oct 22
Growing season
175 days
Hardiness zone
6b
Explore more for St. Clair, PA: full frost dates · planting calendar · Pennsylvania frost dates
Climate data from the nearest NOAA station, Mahanoy City 2 N, Pa (8.2 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.