GreenlyPhiladelphia: frost dates
United States
In Philadelphia the last spring frost usually comes around 3 April and the first autumn frost around 11 November, which leaves about 222 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 29 April.
| Last spring frost | around 3 April |
|---|---|
| First autumn frost | around 11 November |
| Frost-free days | 222 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Bell Pepper | 8 February | 23 April | 14 May |
| Chili Pepper | 25 February | 10 May | 31 May |
| Corn | — | 22 March | sow 12 April |
| Cucumber | 12 March | 23 April | 14 May |
| Eggplant | 12 February | 23 April | 14 May |
| Green Beans | 13 February | 22 March | 12 April |
| Melon | 2 March | 23 April | 14 May |
| Peas | — | 20 February | sow 13 March |
| Physalis | 22 February | 8 April | 29 April |
| Pumpkin | 2 March | 8 April | 29 April |
| Sweet Corn | — | 22 March | sow 12 April |
| Tomato | 10 February | 8 April | 29 April |
| Watermelon | 22 March | 23 April | 14 May |
| Zucchini | 7 March | 8 April | 29 April |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.
Philadelphia: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Planted in autumn
| Crop | Plant around |
|---|---|
| Crocus | 12 October |
| Daffodil | 12 October |
| Garlic | 12 October |
| Hyacinth | 12 October |
| Lily | 12 October |
| Tulip | 12 October |
A month before the first autumn frost, so the roots grow before winter.