Northport, NY 11721 Frost Dates
11721, near Northport, NY: the frost window
Typically, the last spring freeze lands around 04/09, roughly 224 days out. Fall's first freeze usually shows up around 11/10, roughly 215 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Northport 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
Northport's growing season runs out in roughly 11 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/09 isn't a guarantee
04/09 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/23 and only about 1 year in 10 sees frost after that.
Northport against the rest of the dataset
Northport's growing season runs about 215 days, ranking 14,070 of 40,283 US ZIP codes measured here, longest to shortest. Within NY, it ranks 219 of 1,951.
Learn more
Two guides worth reading on 11721: zone vs. frost date, on why Zone 7b and Northport's frost date answer different questions, and the frost range, on how to read the range around Northport's dates instead of trusting one.