Last frost date in Philadelphia, PA
Expect the last frost in Philadelphia around March 30. Frost after April 12 happens in only one year out of ten. The first fall frost usually arrives about November 17, which leaves 232 frost-free days. An early freeze before November 4 happens one year in ten.
- Safe after (10% risk)
- Apr 12
- Average first frost
- Nov 17
- Frost-free season
- 232 days
- Hard freeze (28°F) ends
- Mar 17
No frost in the next 7 nights
National Weather Service forecast, updated Oct 22, 11:10 UTC
- ThuOct 2244°
- FriOct 2337°
- SatOct 2438°
- SunOct 2541°
- MonOct 2648°
- TueOct 2747°
- WedOct 2847°
Planting calendar for Philadelphia
Windows count forward or back from the average frost dates above. Click a crop for dates across Pennsylvania.
TomatoesApr 6–Apr 20
PumpkinsApr 13–Apr 27
SunflowersMar 30–Apr 20
CucumbersApr 13–Apr 20
CornApr 6–Apr 20
Sweet potatoesApr 20–May 4
WatermelonApr 13–Apr 27
Green beansApr 6–Apr 27
ZucchiniApr 6–Apr 20
OkraApr 20–May 4
PeppersApr 13–Apr 27
BasilApr 6–Apr 20
Butternut squashApr 6–Apr 20
CantaloupeApr 13–Apr 27
EggplantApr 13–Apr 27
PotatoesMar 2–Mar 16
OnionsFeb 16–Mar 9
CarrotsMar 9–Apr 13
LettuceMar 16–Apr 6
BroccoliMar 2–Mar 16
BeetsMar 2–Apr 13
PeasFeb 16–Mar 2
CabbageMar 2–Mar 16
RadishesFeb 23–Apr 6
Brussels sproutsMar 16–Mar 30
SpinachFeb 16–Mar 9
CilantroMar 16–Apr 6
KaleMar 2–Mar 16
Collard greensMar 2–Mar 16
TurnipsMar 2–Mar 16
DillMar 30–Apr 13
CeleryApr 6–Apr 13
CauliflowerMar 16–Mar 30
LeeksMar 16–Mar 30
Swiss chardMar 16–Apr 13
ParsleyMar 16–Apr 6
Tulip bulbsNov 3–Dec 8
GarlicOct 15–Nov 30
Daffodil bulbsOct 15–Nov 30
StrawberriesMar 2–Mar 16
AsparagusMar 2–Mar 16Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Mar 15 | Mar 30 | Apr 12 | Nov 4 | Nov 17 | Dec 4 |
| Hard freeze, 28°F | Mar 1 | Mar 17 | Mar 31 | Nov 12 | Nov 29 | Dec 18 |
Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.
Where these numbers come from
NOAA station Phila Franklin Inst (USC00366886) sits 4.1 miles from the center of Philadelphia at 60 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.
Questions
When is the last frost in Philadelphia, PA?
The average last frost date in Philadelphia is March 30, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after April 12.
When is the first frost in Philadelphia?
The first frost in fall usually comes around November 17. One year in ten it arrives before November 4.
How long is the growing season in Philadelphia?
About 232 days between the average last and first frost.
When should I plant tomatoes in Philadelphia?
Plant tomato seedlings outside from April 6 to April 20. Start seeds indoors six to eight weeks earlier.
Nearby in Pennsylvania
- Drexel HillApr 2
- NorristownApr 8
- King of PrussiaApr 8
- ChesterMar 30
- LevittownApr 21
- PhoenixvilleApr 18
- PottstownApr 20
- AllentownApr 20
- BethlehemApr 20
- EastonApr 18
- ReadingApr 14
- LancasterApr 19