GreenlyWashington, D.C.: frost dates
United States
In Washington, D.C. the last spring frost usually comes around 31 March and the first autumn frost around 16 November, which leaves about 230 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 15 April.
| Last spring frost | around 31 March |
|---|---|
| First autumn frost | around 16 November |
| Frost-free days | 230 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 | 29 January | 13 April | 4 May |
| Chili Pepper | 17 February | 2 May | 23 May |
| Corn | — | 17 March | sow 7 April |
| Cucumber | 2 March | 13 April | 4 May |
| Eggplant | 2 February | 13 April | 4 May |
| Green Beans | 8 February | 17 March | 7 April |
| Melon | 20 February | 13 April | 4 May |
| Peas | — | 17 February | sow 10 March |
| Physalis | 8 February | 25 March | 15 April |
| Pumpkin | 16 February | 25 March | 15 April |
| Sweet Corn | — | 17 March | sow 7 April |
| Tomato | 27 January | 25 March | 15 April |
| Watermelon | 12 March | 13 April | 4 May |
| Zucchini | 21 February | 25 March | 15 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.
Washington, D.C.: 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 | 17 October |
| Daffodil | 17 October |
| Garlic | 17 October |
| Hyacinth | 17 October |
| Lily | 17 October |
| Tulip | 17 October |
A month before the first autumn frost, so the roots grow before winter.