Washington, DC 20066 Frost Dates
Washington, DC: when does the frost end?
Around 03/29 is the usual last spring frost, about 213 days away. Fall's first freeze usually shows up around 11/08, roughly 224 days after the last spring frost.
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.
Stretching the season past the first frost
With roughly 10 weeks until Washington's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 03/29 isn't a guarantee
03/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/11 and only about 1 year in 10 sees frost after that.
Washington against the rest of the dataset
Washington's growing season runs about 224 days, ranking 11,552 of 40,283 US ZIP codes measured here, longest to shortest. Within DC, it ranks 80 of 246.
Learn more
Before leaning on 20066's figures: local microclimates explains what one yard in Washington can differ from the 20066 normal, while zone vs. frost date explains why Zone 8a and Washington's frost date answer different questions.