St. Clair, PA Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for St. Clair, a community in Blair County, Pennsylvania.
Today
84°F
Patchy Fog then Sunny
Patchy fog before 10am. Sunny, with a high near 84. East wind 0 to 3 mph.
7-day forecast for St. Clair
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 84°F | Patchy Fog then Sunny | 0 to 3 mph E | 0% |
| Tonight | 63°F | Partly Cloudy then Patchy Fog | 0 to 3 mph E | 7% |
| Wednesday | 83°F | Patchy Fog then Chance Showers And Thunderstorms | 0 to 3 mph SE | 47% |
| Wednesday Night | 68°F | Chance Showers And Thunderstorms | 0 to 3 mph SE | 41% |
| Thursday | 86°F | Showers And Thunderstorms | 0 to 5 mph SW | 86% |
| Thursday Night | 68°F | Showers And Thunderstorms then Slight Chance Showers And Thunderstorms | 2 mph SW | 86% |
| Friday | 86°F | Showers And Thunderstorms | 0 to 5 mph W | 77% |
| Friday Night | 67°F | Showers And Thunderstorms then Chance Showers And Thunderstorms | 2 mph SW | 77% |
| Saturday | 85°F | Slight Chance Rain Showers then Chance Showers And Thunderstorms | 1 to 6 mph W | 44% |
| Saturday Night | 67°F | Chance Showers And Thunderstorms | 3 mph W | 44% |
| Sunday | 87°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 1 to 6 mph W | 16% |
| Sunday Night | 69°F | Slight Chance Showers And Thunderstorms then Partly Cloudy | 3 mph W | 16% |
| Monday | 88°F | Mostly Sunny then Slight Chance Showers And Thunderstorms | 3 to 9 mph W | 21% |
| Monday Night | 68°F | Slight Chance Showers And Thunderstorms | 2 to 8 mph W | 21% |
Forecast source: National Weather Service (api.weather.gov) for St. Clair (40.478, -78.228). Updated through the day.
Growing snapshot for St. Clair
Last spring frost
Apr 19
First fall frost
Oct 28
Growing season
191 days
Hardiness zone
6b
More local growing data for St. Clair: nearby ZIP 16693 weather · frost dates · planting calendar · Pennsylvania frost dates
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Climate data from the nearest NOAA station, Raystown Lake 2, Pa (9.8 mi from St. Clair). Frost dates are 1991–2020 averages, not a forecast. Page updated Aug 4, 2026.