Portsmouth, VA 23705 Frost Dates
23705, near Portsmouth, VA: the frost window
Around 03/16 is the usual last spring frost, about 200 days away. Fall's first freeze usually shows up around 11/26, roughly 255 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 13 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
03/16 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 02/26 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 04/01 and only about 1 year in 10 sees frost after that.
Portsmouth against the rest of the dataset
At roughly 255 frost-free days, Portsmouth places 6,886 of 40,283 ZIP codes in this dataset. Within VA, it ranks 12 of 1,178.
Learn more
Two guides worth reading on 23705: 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 23705 normal.