Washington, DC 20240 Frost Dates
20240, near Washington, DC: the frost window
Around 03/24 is the usual last spring frost, about 208 days away. Fall's first freeze usually shows up around 11/18, roughly 241 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
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.
The actual range around Washington's last frost
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
About 241 days separate Washington's last and first frost, putting it 8,431 of 40,283 ZIP codes nationally. Within DC, it ranks 12 of 246.
Learn more
Two guides worth reading on 20240: local microclimates, on what one yard in Washington can differ from the 20240 normal, and zone vs. frost date, on why Zone 8a and Washington's frost date answer different questions.