Rochester, NH 03821 Frost Dates
Rochester, NH: when does the frost end?
Around 04/30 is the usual last spring frost, about 245 days away. Fall's first freeze usually shows up around 10/09, roughly 161 days after the last spring frost.
Rochester sits in USDA Zone 6a (-10 to -5°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
With roughly 6 weeks until Rochester's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 04/30 isn't a guarantee
04/30 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/18 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/13 and only about 1 year in 10 sees frost after that.
Rochester against the rest of the dataset
Rochester's growing season runs about 161 days, ranking 31,954 of 40,283 US ZIP codes measured here, longest to shortest. Within NH, it ranks 56 of 260.
Learn more
Before leaning on 03821's figures: local microclimates explains what one yard in Rochester can differ from the 03821 normal, while zone vs. frost date explains why Zone 6a and Rochester's frost date answer different questions.