Frost Dates for 43140 — London, Ohio

Half of springs at London Fish Hatchery, OH see their last 32°F night by April 24; only one in ten is past it by April 10, and one in ten still has one after May 10. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 4 20%, and after May 10 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 18 in half of years, as early as October 5 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around October 29; in spring the one-in-ten date for 28°F is April 30, 10 days before the 32°F one. The freeze-free season lasts 175 days in a typical year, shorter than at 68% of the 148 Ohio stations; it reaches 195 days one year in ten and falls short of 157 one year in ten. On average 132 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 10 days longer, to about May 4, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 2 and March 11.

July is the warmest month at London Fish Hatchery, OH, averaging 82°F by day and 63°F at night; January is the coldest at 33°F and 19°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 30% of years.

Warmth for growing adds up to 3,022 growing degree days a year (base 50°F), fewer than at 77% of the 148 Ohio stations. 35% of them (1,070) have built up by the end of June, and July adds the most, 694. Precipitation totals 42.4 inches a year, most in July (5.0") and least in February (2.3"); May to September bring 48% of it.

The nearest other station, Springfield Wtp, OH, 20 miles west of London and 169 feet lower, has a last frost 1 day later (April 25), a first frost 1 day later (October 19).

The first measurable snow (0.1 inch or more) in London usually arrives around December 25, and the last of the season around March 10. Those are the middle dates across the winters of 1991–2020 at London Fish Hatchery, OH, 3.9 miles away: half of years saw snow earlier, half later. Snow fell in 94% of those winters. The last 32°F night of spring typically comes 45 days after the last snow.

ZIP 43140 is 4 miles from London Fish Hatchery, OH, which stands at 1,120 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 43140 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.