Washington, District of Columbia: planting zone & frost dates
Washington is in USDA plant hardiness zone 7b, where the average coldest winter night reaches 5 to 10°F (-15.0 to -12.2°C). The typical last spring frost is around Apr 3 and the first fall frost around Nov 2.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 11 | Oct 26 |
| Typical planning date (30% risk) | Apr 3 | Nov 2 |
| Median (50%) | Mar 29 | Nov 8 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station NATL ARBORETUM DC, MD (USC00186350), 2.5 mi (4.1 km) from the city center and 7 ft lower than the city center (-2 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Washington
Washington spans more than one half-zone. Share of the city's land area by zone (via its 54 ZIP codes): 7b (57%), 8a (43%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Washington and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 20019 | 8a | 10.0% |
| 20011 | 7b | 8.8% |
| 20032 | 8a | 8.6% |
| 20002 | 8a | 8.4% |
| 20020 | 7b | 7.5% |
| 20016 | 7b | 7.2% |
| 20015 | 7b | 5.7% |
| 20007 | 7b | 5.1% |
| 20008 | 7b | 5.1% |
| 20018 | 7b | 4.9% |
| 20003 | 8a | 3.7% |
| 20017 | 7b | 3.6% |
| 20024 | 8a | 3.6% |
| 20012 | 7b | 3.4% |
| 20001 | 8a | 3.3% |
| 20009 | 7b | 2.2% |
| 20010 | 7b | 1.6% |
| 20037 | 8a | 1.2% |
| 20373 | 8a | 0.8% |
| 20005 | 8a | 0.7% |
| 20006 | 8a | 0.6% |
| 20317 | 7b | 0.6% |
| 20036 | 8a | 0.5% |
| 20057 | 7b | 0.3% |
| 20064 | 7b | 0.3% |
| 20230 | 8a | 0.2% |
| 20319 | 8a | 0.2% |
| 20422 | 7b | 0.2% |
| 20560 | 8a | 0.2% |
| 20565 | 8a | 0.2% |
| 20052 | 8a | 0.1% |
| 20388 | 8a | 0.1% |
| 20520 | 8a | 0.1% |
| 20540 | 8a | 0.1% |
| 20566 | 8a | 0.1% |
| 20045 | 8a | 0.0% |
| 20204 | 8a | 0.0% |
| 20220 | 8a | 0.0% |
| 20240 | 8a | 0.0% |
| 20245 | 8a | 0.0% |
| 20250 | 8a | 0.0% |
| 20260 | 8a | 0.0% |
| 20390 | 8a | 0.0% |
| 20408 | 8a | 0.0% |
| 20415 | 8a | 0.0% |
| 20418 | 8a | 0.0% |
| 20427 | 8a | 0.0% |
| 20431 | 8a | 0.0% |
| 20510 | 8a | 0.0% |
| 20530 | 8a | 0.0% |
| 20535 | 8a | 0.0% |
| 20542 | 7b | 0.0% |
| 20551 | 8a | 0.0% |
| 20591 | 8a | 0.0% |
Vegetable planting calendar for Washington
Dates are counted from the 30%-risk frost dates above (last frost Apr 3, first frost Nov 2). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 6 – Feb 20 | Apr 10 – Apr 24 | — | — |
| Pepper | Jan 23 – Feb 6 | Apr 17 – May 1 | — | — |
| Lettuce | Feb 20 – Mar 6 | Mar 20 – Apr 10 | Mar 6 – Apr 17 | Aug 24 – Sep 21 |
| Green Beans | — | — | Apr 10 – May 15 | Aug 10 – Aug 24 |
| Sweet Corn | — | — | Apr 10 – May 8 | — |
| Zucchini & Summer Squash | Mar 6 – Mar 13 | Apr 10 – Apr 24 | Apr 10 – May 1 | Aug 10 – Aug 24 |
| Cucumber | Mar 6 – Mar 13 | Apr 17 – Apr 24 | Apr 10 – May 1 | Aug 10 – Aug 24 |
| Carrot | — | — | Mar 13 – Apr 17 | Aug 10 – Aug 24 |
| Onion | Jan 9 – Jan 23 | Mar 6 – Mar 20 | — | — |
| Potato | — | Mar 6 – Mar 27 | — | — |
| Basil | Feb 20 – Mar 6 | Apr 17 – May 1 | Apr 17 – May 8 | — |
| Spinach | — | — | Feb 20 – Mar 20 | Sep 7 – Oct 5 |
| Kale | Feb 6 – Feb 20 | Mar 6 – Mar 27 | Mar 6 – Mar 27 | Aug 24 – Sep 21 |
| Broccoli | Feb 6 – Feb 20 | Mar 20 – Apr 10 | — | Aug 10 – Aug 24 |
| Peas | — | — | Feb 20 – Mar 13 | Aug 24 – Sep 7 |
| Eggplant | Jan 23 – Feb 6 | Apr 17 – May 1 | — | — |
| Cabbage | Feb 6 – Feb 20 | Mar 6 – Mar 20 | — | Aug 10 – Aug 24 |
| Radish | — | — | Feb 27 – Apr 17 | Sep 21 – Oct 19 |
| Strawberry | — | Mar 6 – Mar 27 | — | — |
| Beets | — | — | Mar 13 – Apr 24 | Aug 24 – Sep 7 |
Nearby cities in District of Columbia
More: all District of Columbia cities · other zone 7b cities: New York, NY, Philadelphia, PA, Oklahoma City, OK, Nashville, TN, Baltimore, MD, Albuquerque, NM, Tulsa, OK, Newark, NJ
Washington gardening questions
When is the last frost in Washington, DC?
Plan around Apr 3. At NOAA's Natl Arboretum Dc, MD station, 2.5 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Mar 29, and after Apr 11 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 17. The last frost is fairly predictable here: only 27 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Washington, DC?
Start seeds indoors Feb 6 – Feb 20 and set transplants outside Apr 10 – Apr 24, once nights stay above 50°F and the soil is near 60°F. That leaves 213 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Washington?
About 224 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 205 days, and in 1 year in 10 it runs 243 days or more. In fall there is a 10% chance of frost by Oct 26 and a 30% chance by Nov 2.
When should I plant a fall garden in Washington?
Count back from the first fall frost (Nov 2): transplant broccoli Aug 10 – Aug 24; sow kale Aug 24 – Sep 21; sow lettuce Aug 24 – Sep 21; sow radishes Sep 21 – Oct 19. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 20. How the math works: succession and fall planting.
Did Washington's hardiness zone change on the 2023 map?
Yes. Most of Washington was zone 7a on the 2012 map and is zone 7b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
Is all of Washington in zone 7b?
No. Zone 7b covers about 57% of the city's land; the rest is in 8a (43%), measured across the city's 54 ZIP codes. Check your own ZIP code in the table above or with the ZIP lookup.