When to plant in Norristown, PA
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Norristown, Pennsylvania — all computed from Norristown's nearest NOAA weather station.
In zone 7a, Norristown 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 Norristown’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 Norristown, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 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.
Norristown planting FAQ
When is the last spring frost in Norristown, PA?
Plan for the last spring frost in Norristown around April 8 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Norristown, PA?
The first fall frost in Norristown typically arrives around October 31 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Norristown in?
Norristown 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 Norristown?
Norristown 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 Norristown?
For Norristown, 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 Norristown
An email when it’s time to start seeds, transplant, and sow — timed to Norristown’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- King of Prussia · 4 km
- Ardmore · 14 km
- Lansdale · 14 km
- Bala Cynwyd · 16 km
- Phoenixville · 16 km
- Montgomeryville · 17 km
- Broomall · 17 km
- Roslyn · 17 km
Frost dates recorded at NORRISTOWN, 1 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 Norristown, PA — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00366370. Retrieved from https://blissgarden.com/pennsylvania/norristown.