Portsmouth, OH 45630 Frost Dates
When can you plant in Portsmouth, OH?
Typically, the last spring freeze lands around 04/17, roughly 232 days out. The first fall frost typically arrives around 10/25, about 191 frost-free days later.
Portsmouth sits in USDA Zone 6b (-5 to 0°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.
What to do before the first frost
About 8 weeks of growing season left in Portsmouth before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/17 is the middle of 30 years of NOAA records, not a promise. Plant by 04/03 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Portsmouth compares
About 191 days separate Portsmouth's last and first frost, putting it 20,724 of 40,283 ZIP codes nationally. Within OH, it ranks 284 of 1,383.
Learn more
local microclimates covers what one yard in Portsmouth can differ from the 45630 normal. zone vs. frost date covers why Zone 6b and Portsmouth's frost date answer different questions.