When Is the Last Frost in Washington, D.C.?
The average last spring frost in Washington, D.C. falls between March 24 and April 9 for most ZIP codes, with a statewide median of March 24. At the average date a later frost is still a coin flip, so tender plants wait for the safer 90% date.
| City | Last frost | 90% safe after | First frost | Growing season |
|---|---|---|---|---|
| Washington | Mar 29 | Apr 11 | Nov 8 | 224 days |
Last and first frost: 50% (median) dates of the last spring and first fall 32 °F night. 90% safe after: only a 10% chance of a later spring frost. First frost dates in January fall in the following winter. Each city uses the NOAA station nearest the ZIP code closest to its center.
When Is the First Frost in Washington, D.C.?
The average first fall frost in Washington, D.C. arrives between October 31 and November 18 for most ZIP codes, with a median of November 18. Tomatoes, peppers, basil and squash are damaged at 32 °F, so harvest or cover them before then.
Fall frost can come early: Washington has a 10% chance of frost before October 26. Hardy crops such as kale, spinach and cabbage tolerate light frosts and keep producing after the first frost date.
When to Plant Tomatoes in Washington, D.C.?
Transplant tomatoes in Washington, D.C. 1 to 2 weeks after the local average last frost, once nights stay above about 50 °F: Apr 5 – Apr 12 in Washington. Start seeds indoors 6 to 8 weeks before the last frost.
| City | Start seeds indoors | Transplant outdoors | Lowest-risk transplant |
|---|---|---|---|
| Washington | Feb 1 – Feb 15 | Apr 5 – Apr 12 | after Apr 11 |
Indoors: 6–8 weeks before the average last frost. Outdoors: 1–2 weeks after it. Lowest-risk: after the date with only a 10% chance of a later frost. Rules of thumb; check the 10-day forecast and wait for soil near 60 °F.
Tomatoes stall below about 50 °F at night and are killed by frost, so a week or two of waiting after the average date costs little. The tomato plant care guide covers light, watering and feeding once plants are in the ground. With a median growing season of 241 days, Washington, D.C. gardeners often also set out a second tomato crop in mid-summer for fall harvest.
What Can You Plant in Washington and When?
Washington's average last frost of March 29 anchors its spring planting calendar: peas and spinach go in from February 15, broccoli and lettuce transplants from March 1, and tomatoes, peppers and squash after April 5.
| Crop | Start seeds indoors | Plant outdoors | Frost tolerance |
|---|---|---|---|
| Peas | — | Feb 15 – Mar 1direct sow, 4–6 weeks before last frost | hardy |
| Spinach | — | Feb 15 – Mar 8direct sow, 3–6 weeks before last frost | hardy |
| Radishes | — | Feb 22 – Mar 8direct sow, 3–5 weeks before last frost | hardy |
| Onions (sets) | — | Mar 1 – Mar 15plant, 2–4 weeks before last frost | hardy |
| Potatoes | — | Mar 1 – Mar 15plant, 2–4 weeks before last frost | half-hardy |
| Broccoli & cabbage | Feb 1 – Feb 15 | Mar 1 – Mar 15transplant, 2–4 weeks before last frost | hardy |
| Lettuce | Feb 15 – Mar 1 | Mar 1 – Mar 15transplant, 2–4 weeks before last frost | hardy |
| Beets | — | Mar 1 – Mar 15direct sow, 2–4 weeks before last frost | half-hardy |
| Carrots | — | Mar 8 – Mar 15direct sow, 2–3 weeks before last frost | half-hardy |
| Tomatoes | Feb 1 – Feb 15 | Apr 5 – Apr 12transplant, 1–2 weeks after last frost | tender |
| Basil | Feb 1 – Feb 15 | Apr 5 – Apr 19transplant, 1–3 weeks after last frost | tender |
| Peppers | Jan 18 – Feb 1 | Apr 12 – Apr 19transplant, 2–3 weeks after last frost | tender |
| Eggplant | Jan 18 – Feb 1 | Apr 12 – Apr 19transplant, 2–3 weeks after last frost | tender |
| Green beans | — | Apr 5 – Apr 19direct sow, 1–3 weeks after last frost | tender |
| Sweet corn | — | Apr 5 – Apr 19direct sow, 1–3 weeks after last frost | tender |
| Cucumbers | Mar 1 – Mar 8 | Apr 5 – Apr 19transplant, 1–3 weeks after last frost | tender |
| Squash & zucchini | Mar 1 – Mar 8 | Apr 5 – Apr 19transplant, 1–3 weeks after last frost | tender |
| Watermelon | Mar 1 – Mar 8 | Apr 12 – Apr 19transplant, 2–3 weeks after last frost | tender |
Dates for Washington (last frost Mar 29, NOAA station Natl Arboretum Dc, MD, 2 miles from ZIP 20001). General rules of thumb; wait for soil near 50 °F for most seeds and 60 °F for beans, corn and squash.
How Long Is the Growing Season in Washington, D.C.?
The frost-free growing season in Washington, D.C. lasts about 202 to 241 days for most ZIP codes, with a median of 241 days.
Season length decides which varieties ripen: compare it with the “days to maturity” on seed packets, counted from transplanting for tomatoes and peppers. Planning beds before the season starts helps in short seasons — a plant spacing calculator for vegetable beds shows how many transplants fit.
What Hardiness Zones Are in Washington, D.C.?
Washington, D.C. spans USDA hardiness zones 7b to 8a, with zone 8a the most common. Zones describe winter cold and decide which perennials survive, while frost dates set when to plant annual vegetables and flowers.
The Washington, D.C. planting zone map with the zone of each city shows how the zones are spread across the state and which plants are hardy in all of them.
Frequently Asked Questions
- When is the last frost in Washington, D.C.?
- The average last spring frost in Washington, D.C. falls between March 24 and April 9 for most ZIP codes, with a statewide median of March 24.
- When is the last frost in Washington, Washington, D.C.?
- Washington's average last spring frost is March 29, and by April 11 the chance of a later frost drops to 10%. Its first fall frost averages November 8, giving a 224-day growing season (NOAA station Natl Arboretum Dc, MD).
- When should you plant tomatoes in Washington, D.C.?
- Transplant tomatoes in Washington, D.C. 1 to 2 weeks after the local average last frost, once nights stay above about 50 °F: Apr 5 – Apr 12 in Washington. Start seeds indoors 6 to 8 weeks before the last frost.
- When is the first frost in Washington, D.C.?
- The average first fall frost in Washington, D.C. arrives between October 31 and November 18 for most ZIP codes, with a median of November 18. Harvest tender crops such as tomatoes, peppers and basil before then or cover them on cold nights.
- How long is the growing season in Washington, D.C.?
- The frost-free growing season in Washington, D.C. lasts about 202 to 241 days for most ZIP codes, with a median of 241 days.
Frost data: NOAA National Centers for Environmental Information, 1991–2020 U.S. Climate Normals (32 °F freeze dates by probability). ZIP code and city locations and populations: U.S. Census Bureau Gazetteer files and Vintage 2024 population estimates. Planting windows are general rules of thumb. PlantoScan is not affiliated with or endorsed by these agencies.