When to plant in Williamsport, PA
USDA Zone 6bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Williamsport, Pennsylvania — all computed from Williamsport's nearest NOAA weather station.
Zone 6b means Williamsport sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
The average first fall frost in Williamsport is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
WILLIAMSPORT 2 · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Williamsport’s own odds, recorded at WILLIAMSPORT 2.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 23 | May 7 | Apr 21 | Sep 29 | Oct 11 | Oct 25 |
| 32°F | May 12 | Apr 25 | Apr 10 | Oct 8 | Oct 24 | Nov 5 |
| 28°F | Apr 25 | Apr 10 | Mar 29 | Oct 20 | Nov 4 | Nov 18 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Williamsport, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 35 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Williamsport planting FAQ
When is the last spring frost in Williamsport, PA?
Williamsport's average last spring frost falls near April 25 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Williamsport, PA?
Expect Williamsport's first fall frost near October 24 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Williamsport in?
Williamsport is in USDA hardiness zone 6b. In zone 6b, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Williamsport?
There are roughly 182 frost-free days in Williamsport (a moderate growing season), running from the average last frost around April 25 to the first fall frost near October 24.
When should I plant tomatoes in Williamsport?
In Williamsport, start tomato seeds indoors around February 28–March 14, then transplant seedlings outdoors around May 2 once the danger of frost has passed.
Never miss a window in Williamsport
An email when it’s time to start seeds, transplant, and sow — timed to Williamsport’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Bloomsburg · 55 km
- Berwick · 69 km
- State College · 85 km
- Nanticoke · 87 km
- Pottsville · 93 km
- Hazleton · 95 km
- Mountain Top · 95 km
- Kingston · 96 km
Frost dates recorded at WILLIAMSPORT 2, 4 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Williamsport, PA — Frost Dates & Zone 6b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00369735. Retrieved from https://blissgarden.com/pennsylvania/williamsport.