When to plant in King of Prussia, PA
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for King of Prussia, Pennsylvania — all computed from King of Prussia's nearest NOAA weather station.
In zone 7a, King of Prussia supports a wide range of perennials year-round; the frost dates above are what set your annual vegetable timing.
Frost probability
NORRISTOWN · 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 King of Prussia’s own odds, recorded at NORRISTOWN.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 9 | Apr 22 | Apr 6 | Oct 6 | Oct 20 | Nov 3 |
| 32°F | Apr 23 | Apr 8 | Mar 28 | Oct 14 | Oct 31 | Nov 12 |
| 28°F | Apr 12 | Mar 31 | Mar 15 | Oct 27 | Nov 10 | Nov 22 |
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 King of Prussia, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 15 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.
King of Prussia planting FAQ
When is the last spring frost in King of Prussia, PA?
King of Prussia's average last spring frost falls near April 8 — 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 King of Prussia, PA?
The first fall frost in King of Prussia typically arrives around October 31 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is King of Prussia in?
King of Prussia is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in King of Prussia?
King of Prussia has about 206 frost-free days — a moderate growing season — between the average last spring frost (April 8) and first fall frost (October 31).
When should I plant tomatoes in King of Prussia?
For King of Prussia, sow tomatoes indoors about February 11–February 25 and move the seedlings out around April 15, after the last spring frost.
Never miss a window in King of Prussia
An email when it’s time to start seeds, transplant, and sow — timed to King of Prussia’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Norristown · 4 km
- Ardmore · 13 km
- Phoenixville · 13 km
- Broomall · 14 km
- Bala Cynwyd · 16 km
- Drexel Hill · 18 km
- Lansdale · 18 km
- Lansdowne · 19 km
Frost dates recorded at NORRISTOWN, 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 King of Prussia, PA — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00366370. Retrieved from https://blissgarden.com/pennsylvania/king-of-prussia.