Frost Dates for 45662 — Portsmouth, Ohio

Half of springs at Portsmouth-Sciotoville, OH see their last 32°F night by April 17; only one in ten is past it by April 3, and one in ten still has one after May 5. Planting tender crops after April 24 leaves a 30% risk of a frost on them, after April 28 20%, and after May 5 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 76% of the 148 Ohio stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 25 in half of years, as early as October 11 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 10 days later, around November 4; in spring the one-in-ten date for 28°F is April 20, 15 days before the 32°F one. The freeze-free season lasts 191 days in a typical year, longer than at 84% of the 148 Ohio stations; it reaches 210 days one year in ten and falls short of 167 one year in ten. On average 106 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 13 days longer, to about April 30, and return around October 15. Severe cold of 16°F or below comes every winter, usually between December 14 and February 28.

July is the warmest month at Portsmouth-Sciotoville, OH, averaging 87°F by day and 65°F at night; January is the coldest at 41°F and 23°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 15% of years.

Warmth for growing adds up to 3,784 growing degree days a year (base 50°F), more than at 96% of the 148 Ohio stations. 36% of them (1,377) have built up by the end of June, and July adds the most, 808. Precipitation totals 43.2 inches a year, most in May (4.6") and least in November (2.8"); May to September bring 46% of it.

The nearest other station, Lucasville, OH, 9 miles north of Portsmouth, has a last frost 4 days later (April 21), a first frost 1 day earlier (October 24), a season 6 days shorter.

The first measurable snow (0.1 inch or more) in Portsmouth usually arrives around January 7, and the last of the season around February 9. Those are the middle dates across the winters of 1991–2020 at Greenup Locks & Dam, KY, 9.1 miles away: half of years saw snow earlier, half later. Snow fell in 88% of those winters. The last 32°F night of spring typically comes 67 days after the last snow.

ZIP 45662 is 3 miles from Portsmouth-Sciotoville, OH, which stands at 540 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 45662 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°C) over 1991–2020; a zone describes winter lows, not frost dates.