Rocky Hill, NJ 08553 Frost Dates
08553, near Rocky Hill, NJ: the frost window
The last spring frost here typically falls around 04/25, about 240 days from today. Fall's first freeze usually shows up around 10/16, roughly 173 days after the last spring frost.
Zone 7a (0 to 5°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 Rocky Hill, not a forecast for this year.
Stretching the season past the first frost
Rocky Hill's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/25 isn't a guarantee
04/25 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/12 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/12 and only about 1 year in 10 sees frost after that.
Rocky Hill against the rest of the dataset
At roughly 173 frost-free days, Rocky Hill places 28,022 of 40,283 ZIP codes in this dataset. Within NJ, it ranks 856 of 906.
Learn more
Two guides worth reading on 08553: zone vs. frost date, on why Zone 7a and Rocky Hill's frost date answer different questions, and the frost range, on how to read the range around Rocky Hill's dates instead of trusting one.