Philadelphia, PA Frost Dates
Average frost dates, USDA hardiness zone, and growing season length for Philadelphia, Pennsylvania.
Gardening in Philadelphia
Philly's gardening culture runs as deep as its history. From the community gardens of West Philadelphia to the rowhome container gardens of South Philly, this city grows food with the same scrappy, no-nonsense attitude it brings to everything else. Nobody here needs permission to start planting.
Four honest seasons. Winters are cold enough to kill pests and vernalize your garlic. Summers are hot and humid enough to grow spectacular tomatoes, peppers, and basil. Spring arrives in dramatic fashion — the cherry blossoms along the Schuylkill are the starting gun for planting season. Fall is long, warm, and golden, stretching the harvest deep into November.
Eagles fans are used to passionate, all-in commitment to something everyone else thinks is crazy — which is also a perfect description of starting tomato seeds indoors in February during a nor'easter. The Italian Market's produce vendors have been the standard Philly gardeners measure themselves against for over a century.
What This Means for Philadelphia Gardeners
The average last spring frost in Philadelphia is around March 30, and the average first fall frost arrives around November 10. That gives you approximately 225 frost-free days to work with.
That's a generous season. You have time for full-size tomatoes, long-season peppers, and even watermelons without the anxiety of racing the frost. Start warm-season seeds indoors 6-8 weeks before your last frost to hit the ground running. Fall planting is your second opportunity — garlic, kale, lettuce, and broccoli all go in 8-10 weeks before your first frost for harvest into late autumn.
These dates are based on NOAA 30-year Climate Normal data for the Philadelphia area. Your actual frost dates could shift 2-3 weeks in either direction in any given year. Learn more about our data sources.
What to Grow in Philadelphia
Philadelphia's 225-day growing season is generous — long enough for two full growing windows (spring and fall) with warm-season crops between them. You can grow the full range of vegetables, herbs, and flowers with proper timing. Focus on heat-tolerant varieties for midsummer and cool-season crops for extended fall harvests. Recommended starting points: tomatoes, peppers, beans, cucumbers, squash, garlic, kale, and sunflowers.
See the full Pennsylvania planting guide for all 40 plants: Pennsylvania Planting Calendar. Or enter your zip code for exact planting dates personalized to Philadelphia.
More About Zone 7B
Philadelphia is in USDA Hardiness Zone 7B, which means average annual extreme minimum temperatures between 5°F to 10°F. View the full Zone 7B planting guide.
See the complete planting calendar for Pennsylvania: Pennsylvania Planting Calendar.
Other Cities in Pennsylvania
Frequently Asked Questions
These dates are based on NOAA's 30-year Climate Normal data for the Philadelphia area. They represent historical averages, not predictions. In any given year, the actual last frost could be 2-3 weeks earlier or later. Microclimates within Philadelphia (urban heat islands, hilltops, low-lying valleys) can also shift your local frost dates by a week or more.
Cool-season crops go in 3-4 weeks before your last frost (March 30). Warm-season crops wait until 2 weeks after. You have time for a fall round too — plant cool-season crops again in late summer for harvest into autumn. Enter your zip code for exact dates.