Princeton, NJ 08542 Frost Dates
Princeton, NJ: when does the frost end?
Around 04/25 is the usual last spring frost, about 240 days away. Fall's first freeze usually shows up around 10/16, roughly 173 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Princeton in Zone 7a (0 to 5°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
With roughly 7 weeks until Princeton's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
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.
Princeton against the rest of the dataset
At roughly 173 frost-free days, Princeton places 27,788 of 40,283 ZIP codes in this dataset. Within NJ, it ranks 835 of 906.
Learn more
Before leaning on 08542's figures: local microclimates explains what one yard in Princeton can differ from the 08542 normal, while zone vs. frost date explains why Zone 7a and Princeton's frost date answer different questions.