Frost Dates for Philadelphia, PA 19124

Last spring frost April 22 · First fall frost October 20 · 181 frost-free days · USDA Zone 7b

Frost probability for 19124

Frost10%50%90%
Spring (last frost)May 3April 22April 7
Fall (first frost)October 6October 20November 5

Dates come from NOAA 1971–2000 freeze probabilities at the nearest reporting station (18.9 km away); the 50% date is the median year.

Frost dates by ZIP code in Philadelphia, PA

ZIPLast spring frost (50%)First fall frost (50%)Zone
19124April 22October 207b
19120April 17October 257b
19111April 22October 207b
19143April 6November 47b
19149April 22October 207b
19104April 11October 287b
19134April 22October 207b
19140April 17October 257b
19144April 17October 257b
19148April 11October 287b
19131April 6November 47b
19145April 11October 287b
19139April 6November 47b
19121April 11October 287b
19146April 11October 287b
19147April 11October 287b
19128April 17October 257b
19136April 22October 207b
19152April 22October 207b
19115April 22October 207b
19135April 22October 207b
19154April 23October 187b
19116April 23October 187b
19151April 6November 47b
19132April 17October 257b
19141April 17October 257b
19138April 17October 257b
19114April 22October 207b
19130April 11October 287b
19142April 6November 47b
19119April 17October 257b
19103April 11October 287b
19122April 11October 287b
19125April 11October 287b
19133April 17October 257b
19150April 17October 257b
19123April 11October 287b
19126April 17October 257b
19107April 11October 287b
19106April 11October 287b
19153April 6November 47b
19129April 17October 257b
19118April 17October 257b
19137April 22October 207b
19102April 11October 287b
19127April 17October 257b
19108April 11October 287b
19109April 11October 287b
19112April 6November 47b
19113April 6November 47b

Month by month in Philadelphia

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart peppers and eggplant indoors 8–10 weeks before your last frost (around April 22). Start tomatoes about two weeks later, 6–8 weeks before last frost.
MarchStart herbs, basil, and squash indoors (4–6 weeks before frost). Direct sow peas, spinach, and lettuce if soil is workable.
AprilLast frost around April 22. Transplant cold-hardy crops (broccoli, kale, cabbage). Harden off tomato and pepper seedlings.
MayFrost has passed. Transplant tomatoes, peppers, and basil outdoors. Direct sow beans, cucumbers, squash, and zucchini.
JuneSuccession plant lettuce and greens. Keep beds weeded and watered consistently.
JulyHarvest regularly to encourage production. Monitor for pests and disease.
AugustMidsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall.
SeptemberFirst fall frost approaching (around October 20). Transplant fall brassicas. Sow spinach, arugula, and radishes.
OctoberFirst frost around October 20. Harvest tomatoes and peppers before frost. Cover cold-hardy crops with row covers to extend the season.
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

What grows in a 181-day season

Frequently Asked Questions

What is the last frost date for Philadelphia, PA (ZIP 19124)?

The median last spring frost date for Philadelphia, PA (ZIP code 19124) is around April 22. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.

What is the first fall frost date in Philadelphia, PA?

The median first fall frost date for Philadelphia, PA is around October 20. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses.

How long is the growing season in Philadelphia, PA?

The frost-free growing season in Philadelphia is about 181 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side.

What USDA hardiness zone is Philadelphia, PA?

Based on frost date patterns, Philadelphia falls approximately in 7b. USDA hardiness zones are determined by average annual minimum winter temperatures and guide both plant selection and planting timing for your location.

When should I start tomatoes indoors in Philadelphia, PA?

Start tomato seeds indoors 6–8 weeks before your last frost date (around April 22). For Philadelphia, that's roughly February 26 to March 11. Transplant outdoors 1–2 weeks after your last frost.

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