Frost dates for 19144Philadelphia, PA
The average last spring frost in Philadelphia is March 30 and the average first fall frost is November 17, giving a typical growing season of about 232 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 30
- Average first fall frost
- Nov 17
- Growing season
- 232 days
Safer after Apr 12 (1-in-10 risk)
Possible by Nov 4 (1-in-10 risk)
First frost typically in 14 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Mar 27 · Apr 8 · Apr 23 | Oct 23 · Nov 5 · Nov 20 | 211 days | 100% |
| Frost / freeze (32°F) | Mar 15 · Mar 30 · Apr 12 | Nov 4 · Nov 17 · Dec 4 | 232 days | 100% |
| Hard freeze (28°F) | Mar 1 · Mar 17 · Mar 31 | Nov 12 · Nov 29 · Dec 18 | 257 days | 100% |
Planting calendar for Philadelphia
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Feb 27 – May 5 |
| Tomatoes | Transplant outdoors | Apr 15 – Jul 28 |
| Peppers | Start seeds indoors | Feb 27 – Mar 30 |
| Peppers | Transplant outdoors | Apr 29 – May 30 |
| Eggplant | Start seeds indoors | Mar 16 – Apr 14 |
| Eggplant | Transplant outdoors | Apr 29 – May 30 |
| Cucumbers | Sow outdoors | Apr 29 – Aug 7 |
| Summer squash | Sow outdoors | Apr 15 – May 30 |
| Winter squash & pumpkins | Sow outdoors | Apr 29 – May 30 |
| Snap beans | Sow outdoors | Apr 15 – Aug 30 |
| Sweet corn | Sow outdoors | Apr 15 – Jul 28 |
| Watermelon & cantaloupe | Sow outdoors | Apr 29 – May 30 |
| Okra | Sow outdoors | Apr 22 – May 15 |
| Peas | Sow outdoors (spring) | Feb 27 – Apr 14 |
| Potatoes | Plant outdoors (spring) | Feb 27 – Apr 29 |
| Onions | Start seeds indoors (spring) | Jan 16 – Feb 12 |
| Onions | Transplant outdoors (spring) | Mar 16 – Apr 14 |
| Broccoli | Start seeds indoors (spring) | Feb 9 – Mar 15 |
| Broccoli | Transplant outdoors (spring) | Mar 16 – Apr 14 |
| Broccoli | Start seeds indoors (fall) | Jul 18 – Jul 28 |
| Broccoli | Transplant outdoors (fall) | Aug 17 – Aug 28 |
| Cabbage | Start seeds indoors (spring) | Jan 30 – Feb 27 |
| Cabbage | Transplant outdoors (spring) | Feb 27 – Mar 30 |
| Cabbage | Start seeds indoors (fall) | Jul 8 – Aug 7 |
| Cabbage | Transplant outdoors (fall) | Aug 7 – Sep 7 |
| Leaf lettuce | Sow outdoors (spring) | Feb 27 – May 15 |
| Leaf lettuce | Sow outdoors (fall) | Aug 7 – Sep 23 |
| Spinach | Sow outdoors (spring) | Feb 20 – Apr 5 |
| Spinach | Sow outdoors (fall) | Aug 24 – Sep 28 |
| Radishes | Sow outdoors (spring) | Feb 27 – Apr 19 |
| Radishes | Sow outdoors (fall) | Aug 7 – Oct 8 |
| Kale | Sow outdoors (spring) | Mar 16 – Apr 5 |
| Kale | Sow outdoors (fall) | Jul 31 – Sep 7 |
| Carrots | Sow outdoors (spring) | Mar 30 – May 15 |
| Carrots | Sow outdoors (fall) | Jul 8 – Aug 23 |
| Garlic | Plant outdoors (fall) | Nov 7 – Dec 8 |
Where these dates come from
ZIP code 19144 is matched to the NOAA station Phila Franklin Inst, PA, 8.4 km away, at 60 ft elevation (173 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Phila Franklin Inst, PA (used) | 60 ft | Mar 30 | Nov 17 |
| Philadelphia Ne Ap, PA | 100 ft | Apr 4 | Nov 7 |
| Pennsauken 1N, NJ | 46 ft | Apr 15 | Oct 31 |
| Norristown, PA | 62 ft | Apr 8 | Oct 31 |
Frost dates near Philadelphia
- Philadelphia, PA 19141 · last Mar 30, first Nov 17
- Bala Cynwyd, PA 19004 · last Mar 30, first Nov 17
- Elkins Park, PA 19027 · last Apr 4, first Nov 7
- Wyncote, PA 19095 · last Apr 11, first Nov 1
- Cheltenham, PA 19012 · last Apr 4, first Nov 7
- Merion Station, PA 19066 · last Mar 30, first Nov 17
- Narberth, PA 19072 · last Mar 30, first Nov 17
- Glenside, PA 19038 · last Apr 11, first Nov 1
Frequently asked questions
- When is the last frost in Philadelphia, PA?
- For ZIP code 19144, the average last spring frost (32°F) is March 30, based on NOAA 1991-2020 climate normals for the Phila Franklin Inst, PA weather station. There is a 1-in-10 chance of a frost after April 12.
- When is the first frost in Philadelphia, PA?
- The average first fall frost (32°F) is November 17. There is a 1-in-10 chance of frost by November 4, so tender plants are at risk from that point on.
- How long is the growing season in 19144?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 232 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.