Frost dates for 13673Philadelphia, NY
The average last spring frost in Philadelphia is May 14 and the average first fall frost is September 26, giving a typical growing season of about 134 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 14
- Average first fall frost
- Sep 26
- Growing season
- 134 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 12 (1-in-10 risk)
Last frost typically in 192 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) | May 11 · May 27 · Jun 10 | Sep 2 · Sep 16 · Sep 30 | 111 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 14 · May 30 | Sep 12 · Sep 26 · Oct 12 | 134 days | 100% |
| Hard freeze (28°F) | Apr 21 · May 2 · May 17 | Sep 23 · Oct 8 · Oct 27 | 157 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 | Apr 13 – Jun 19 |
| Tomatoes | Transplant outdoors | May 30 – Jun 6 |
| Peppers | Start seeds indoors | Apr 13 – May 14 |
| Peppers | Transplant outdoors | Jun 13 – Jul 14 |
| Eggplant | Start seeds indoors | Apr 30 – May 29 |
| Eggplant | Transplant outdoors | Jun 13 – Jul 14 |
| Cucumbers | Sow outdoors | Jun 13 – Jun 16 |
| Summer squash | Sow outdoors | May 30 – Jul 14 |
| Winter squash & pumpkins | Sow outdoors | Jun 13 – Jul 14 |
| Snap beans | Sow outdoors | May 30 – Jul 9 |
| Sweet corn | Sow outdoors | May 30 – Jun 6 |
| Watermelon & cantaloupe | Sow outdoors | Jun 13 – Jul 14 |
| Okra | Sow outdoors | Jun 6 – Jun 29 |
| Peas | Sow outdoors (spring) | Apr 13 – May 29 |
| Potatoes | Plant outdoors (spring) | Apr 13 – Jun 13 |
| Onions | Start seeds indoors (spring) | Mar 2 – Mar 29 |
| Onions | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (spring) | Mar 26 – Apr 29 |
| Broccoli | Transplant outdoors (spring) | Apr 30 – May 29 |
| Broccoli | Start seeds indoors (fall) | May 27 – Jun 6 |
| Broccoli | Transplant outdoors (fall) | Jun 26 – Jul 7 |
| Cabbage | Start seeds indoors (spring) | Mar 16 – Apr 13 |
| Cabbage | Transplant outdoors (spring) | Apr 13 – May 14 |
| Cabbage | Start seeds indoors (fall) | May 17 – Jun 16 |
| Cabbage | Transplant outdoors (fall) | Jun 16 – Jul 17 |
| Leaf lettuce | Sow outdoors (spring) | Apr 13 – Jun 29 |
| Leaf lettuce | Sow outdoors (fall) | Jun 16 – Aug 2 |
| Spinach | Sow outdoors (spring) | Apr 6 – May 20 |
| Spinach | Sow outdoors (fall) | Jul 3 – Aug 7 |
| Radishes | Sow outdoors (spring) | Apr 13 – Jun 3 |
| Radishes | Sow outdoors (fall) | Jun 16 – Aug 17 |
| Kale | Sow outdoors (spring) | Apr 30 – May 20 |
| Kale | Sow outdoors (fall) | Jun 9 – Jul 17 |
| Carrots | Sow outdoors (spring) | May 14 – Jun 29 |
| Carrots | Sow outdoors (fall) | May 17 – Jul 2 |
| Garlic | Plant outdoors (fall) | Sep 16 – Oct 17 |
Where these dates come from
ZIP code 13673 is matched to the NOAA station Gouverneur 3 Nw, NY, 26.8 km away, at 420 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Gouverneur 3 Nw, NY (used) | 420 ft | May 14 | Sep 26 |
| Watertown, NY | 497 ft | May 2 | Oct 13 |
| Watertown Intl Ap, NY | 318 ft | May 11 | Oct 1 |
| Lowville, NY | 863 ft | May 8 | Oct 1 |
Frost dates near Philadelphia
- Theresa, NY 13691 · last May 2, first Oct 13
- Antwerp, NY 13608 · last May 14, first Sep 26
- Evans Mills, NY 13637 · last May 2, first Oct 13
- Deferiet, NY 13628 · last May 2, first Oct 13
- Great Bend, NY 13643 · last May 2, first Oct 13
- Fort Drum, NY 13602 · last May 2, first Oct 13
- Felts Mills, NY 13638 · last May 2, first Oct 13
- Oxbow, NY 13671 · last May 14, first Sep 26
Frequently asked questions
- When is the last frost in Philadelphia, NY?
- For ZIP code 13673, the average last spring frost (32°F) is May 14, based on NOAA 1991-2020 climate normals for the Gouverneur 3 Nw, NY weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Philadelphia, NY?
- The average first fall frost (32°F) is September 26. There is a 1-in-10 chance of frost by September 12, so tender plants are at risk from that point on.
- How long is the growing season in 13673?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 134 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.