When to plant in St. Marys, PA
USDA Zone 5bSt. Marys, Pennsylvania frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
In zone 5b, St. Marys gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
Frost probability
GLEN HAZEL 2 NE DAM · 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 St. Marys’s own odds, recorded at GLEN HAZEL 2 NE DAM.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 8 | May 27 | May 11 | Sep 12 | Sep 27 | Oct 8 |
| 32°F | May 29 | May 14 | Apr 28 | Sep 24 | Oct 6 | Oct 20 |
| 28°F | May 19 | May 3 | Apr 18 | Oct 2 | Oct 18 | Nov 3 |
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 St. Marys, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 25 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.
St. Marys planting FAQ
When is the last spring frost in St. Marys, PA?
St. Marys's average last spring frost falls near May 14 — 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 St. Marys, PA?
In St. Marys, the first 32°F freeze of fall lands around October 6 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is St. Marys in?
St. Marys is in USDA hardiness zone 5b. In zone 5b, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in St. Marys?
St. Marys has about 145 frost-free days — a short growing season — between the average last spring frost (May 14) and first fall frost (October 6).
When should I plant tomatoes in St. Marys?
For St. Marys, sow tomatoes indoors about March 19–April 2 and move the seedlings out around May 21, after the last spring frost.
Never miss a window in St. Marys
An email when it’s time to start seeds, transplant, and sow — timed to St. Marys’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Olean · 70 km
- State College · 92 km
- Jamestown · 93 km
- Altoona · 106 km
- Indiana · 107 km
- Williamsport · 126 km
- Johnstown · 130 km
- Dunkirk · 132 km
Frost dates recorded at GLEN HAZEL 2 NE DAM, 13 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 St. Marys, PA — Frost Dates & Zone 5b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00363311. Retrieved from https://blissgarden.com/pennsylvania/st-marys.