Baltimore, MD 21031 Frost Dates
21031, near Baltimore, MD: the frost window
The last spring frost here typically falls around 04/02, about 217 days from today. Fall's first freeze usually shows up around 11/07, roughly 220 days after the last spring frost.
Baltimore sits in USDA Zone 7b (5 to 10°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
Baltimore'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.
Why 04/02 isn't a guarantee
04/02 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/20 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/13 and only about 1 year in 10 sees frost after that.
Baltimore against the rest of the dataset
Baltimore's growing season runs about 220 days, ranking 12,631 of 40,283 US ZIP codes measured here, longest to shortest. Within MD, it ranks 138 of 583.
Learn more
Two guides worth reading on 21031: zone vs. frost date, on why Zone 7b and Baltimore's frost date answer different questions, and the frost range, on how to read the range around Baltimore's dates instead of trusting one.