Riverdale Park, MD 20737 Frost Dates
20737, near Riverdale Park, MD: the frost window
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.
The USDA Plant Hardiness Zone Map puts Riverdale Park in Zone 7b (5 to 10°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
Riverdale Park'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.
How much risk comes with planting early here
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.
Riverdale Park against the rest of the dataset
About 224 days separate Riverdale Park's last and first frost, putting it 11,819 of 40,283 ZIP codes nationally. Within MD, it ranks 121 of 583.
Learn more
Two guides worth reading on 20737: local microclimates, on what one yard in Riverdale Park can differ from the 20737 normal, and zone vs. frost date, on why Zone 7b and Riverdale Park's frost date answer different questions.