Stonington, CT 06359 Frost Dates
06359, near Stonington, CT: the frost window
Around 04/11 is the usual last spring frost, about 226 days away. Fall's first freeze usually shows up around 10/31, roughly 201 days after the last spring frost.
Zone 6b (-5 to 0°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 Stonington, not a forecast for this year.
Stretching the season past the first frost
Stonington's growing season runs out in roughly 9 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/11 isn't a guarantee
04/11 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/31 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/26 and only about 1 year in 10 sees frost after that.
Stonington against the rest of the dataset
Stonington's growing season runs about 201 days, ranking 17,592 of 40,283 US ZIP codes measured here, longest to shortest. Within CT, it ranks 41 of 391.
Learn more
Two guides worth reading on 06359: zone vs. frost date, on why Zone 6b and Stonington's frost date answer different questions, and the frost range, on how to read the range around Stonington's dates instead of trusting one.