Washington, DC 20091 Frost Dates
20091, near Washington, DC: the frost window
Typically, the last spring freeze lands around 03/29, roughly 213 days out. Fall's first freeze usually shows up around 11/08, roughly 224 days after the last spring frost.
Zone 8a (10 to 15°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Washington, not a forecast for this year.
Stretching the season past the first frost
Washington's growing season runs out in roughly 10 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
03/29 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
About 224 days separate Washington's last and first frost, putting it 11,568 of 40,283 ZIP codes nationally. Within DC, it ranks 96 of 246.
Learn more
Two guides worth reading on 20091: the frost range, on how to read the range around Washington's dates instead of trusting one, and local microclimates, on what one yard in Washington can differ from the 20091 normal.