Frost Dates for 43334 — Marengo, Ohio

Half of springs at Centerburg 2 SE, OH see their last 32°F night by April 27; only one in ten is past it by April 13, and one in ten still has one after May 13. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 7 20%, and after May 13 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 53% of the 148 Ohio stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 17 in half of years, as early as October 5 one year in ten, and holds off past October 30 one year in ten. A hard freeze of 28°F follows 11 days later, around October 28; in spring the one-in-ten date for 28°F is April 30, 13 days before the 32°F one. The freeze-free season lasts 172 days in a typical year, shorter than at 77% of the 148 Ohio stations; it reaches 190 days one year in ten and falls short of 151 one year in ten. On average 128 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 9 days longer, to about May 6, and return around October 5. Severe cold of 16°F or below comes every winter, usually between December 1 and March 17.

July is the warmest month at Centerburg 2 SE, OH, averaging 83°F by day and 61°F at night; January is the coldest at 34°F and 17°F. A freezing night is all but certain in every month from October 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 37% of years.

Warmth for growing adds up to 2,967 growing degree days a year (base 50°F), fewer than at 81% of the 148 Ohio stations. 36% of them (1,058) have built up by the end of June, and July adds the most, 684. Precipitation totals 44.2 inches a year, most in June (5.0") and least in February (2.5"); May to September bring 48% of it.

The nearest other station, Fredericktown 4 S, OH, 14 miles east of Marengo and 155 feet lower, has a last frost 4 days later (May 1), a first frost 7 days earlier (October 10), a season 11 days shorter.

The first measurable snow (0.1 inch or more) in Marengo usually arrives around November 22, and the last of the season around March 26. Those are the middle dates across the winters of 1991–2020 at Centerburg 2 SE, OH, 11 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 32 days after the last snow.

ZIP 43334 is 11 miles from Centerburg 2 SE, OH, which stands at 1,205 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 43074 (Sunbury). The 2023 USDA Plant Hardiness Zone Map lists ZIP 43334 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.