Portsmouth, VA 23507 Frost Dates
23507, near Portsmouth, VA: the frost window
Around 03/23 is the usual last spring frost, about 207 days away. Fall's first freeze usually shows up around 11/16, roughly 239 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Portsmouth in Zone 8b (15 to 20°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
Portsmouth'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 03/23 isn't a guarantee
03/23 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 03/07 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/06 and only about 1 year in 10 sees frost after that.
Portsmouth against the rest of the dataset
Portsmouth's growing season runs about 239 days, ranking 8,757 of 40,283 US ZIP codes measured here, longest to shortest. Within VA, it ranks 61 of 1,178.
Learn more
Two guides worth reading on 23507: the frost range, on how to read the range around Portsmouth's dates instead of trusting one, and local microclimates, on what one yard in Portsmouth can differ from the 23507 normal.