Washington, DC 20024 Frost Dates
20024, near Washington, DC: the frost window
Typically, the last spring freeze lands around 03/24, roughly 208 days out. Fall's first freeze usually shows up around 11/18, roughly 241 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Washington in Zone 8a (10 to 15°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Washington's growing season runs out in roughly 12 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 03/24 isn't a guarantee
03/24 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/06 and only about 1 year in 10 sees frost after that.
Washington against the rest of the dataset
Washington's growing season runs about 241 days, ranking 8,421 of 40,283 US ZIP codes measured here, longest to shortest. Within DC, it ranks 2 of 246.
Learn more
Two guides worth reading on 20024: local microclimates, on what one yard in Washington can differ from the 20024 normal, and zone vs. frost date, on why Zone 8a and Washington's frost date answer different questions.