Williamstown, PA Weather & Growing Conditions
Today
72°F
Mostly Sunny
Mostly sunny. High near 72, with temperatures falling to around 66 in the afternoon. South wind around 8 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 72°F | Mostly Sunny | 8 mph S | 1% |
| Tonight | 56°F | Mostly Cloudy then Light Rain Likely | 8 mph S | 62% |
| Thursday | 70°F | Light Rain | 5 to 9 mph S | 92% |
| Thursday Night | 53°F | Chance Light Rain | 0 to 3 mph W | 38% |
| Friday | 66°F | Chance Light Rain | 2 mph NW | 29% |
| Friday Night | 44°F | Slight Chance Light Rain then Partly Cloudy | 2 mph NW | 18% |
| Saturday | 58°F | Slight Chance Light Rain | 3 to 8 mph NW | 19% |
| Saturday Night | 38°F | Slight Chance Light Rain | 9 mph W | 19% |
| Sunday | 57°F | Mostly Sunny | 8 mph NW | 6% |
| Sunday Night | 36°F | Partly Cloudy | 7 mph W | 6% |
| Monday | 57°F | Mostly Sunny | 9 mph W | 6% |
| Monday Night | 34°F | Mostly Clear | 7 mph W | 4% |
| Tuesday | 60°F | Mostly Sunny | 6 to 9 mph W | 2% |
| Tuesday Night | 35°F | Mostly Clear | 7 mph W | 0% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Williamstown, PA
Last spring frost
May 1
First fall frost
Oct 16
Growing season
168 days
Hardiness zone
6b
Explore more for Williamstown, PA: full frost dates · planting calendar · Pennsylvania frost dates
Climate data from the nearest NOAA station, Dehart Dam, Pa (10.9 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 4, 2026.