Washington, DC 20230 Frost Dates
Frost dates for Washington, DC, ZIP 20230
Typically, the last spring freeze lands around 03/29, roughly 213 days out. The first fall frost typically arrives around 11/08, about 224 frost-free days later.
Washington sits in USDA Zone 8a (10 to 15°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
Zone 8a around Washington has about 10 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 03/29 isn't a guarantee
03/29 is the middle of 30 years of NOAA records, not a promise. Plant by 03/15 and you're betting against frost in roughly 9 years out of 10. 04/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Washington compares
Washington's growing season runs about 224 days, ranking 11,594 of 40,283 US ZIP codes measured here, longest to shortest. Within DC, it ranks 122 of 246.
Learn more
local microclimates explains what one yard in Washington can differ from the 20230 normal, and zone vs. frost date explains why Zone 8a and Washington's frost date answer different questions.