Frost Dates for 45440 — Dayton, Ohio

Half of springs at Dayton Mcd, OH see their last 32°F night by April 18; 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 25 leaves a 30% risk of a frost on them, after April 30 20%, and after May 5 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 24% 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 13 one year in ten, and holds off past November 7 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 24, 11 days before the 32°F one. The freeze-free season lasts 189 days in a typical year, longer than at 80% of the 148 Ohio stations; it reaches 209 days one year in ten and falls short of 168 one year in ten. On average 107 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 12 days longer, to about April 30, and return around October 16. Severe cold of 16°F or below comes every winter, usually between December 7 and March 6.

July is the warmest month at Dayton Mcd, OH, averaging 87°F by day and 66°F at night; January is the coldest at 36°F and 20°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 20% of years.

Warmth for growing adds up to 3,725 growing degree days a year (base 50°F), more than at 91% of the 148 Ohio stations. 37% of them (1,360) have built up by the end of June, and July adds the most, 812. Precipitation totals 41.6 inches a year, most in April (4.5") and least in February (2.4"); May to September bring 45% of it.

The nearest other station, Dayton Wright Bros Airport, OH, 8 miles southwest of Dayton and 242 feet higher, has a last frost 1 day earlier (April 17), a first frost 1 day later (October 26), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Dayton usually arrives around December 22, and the last of the season around March 9. Those are the middle dates across the winters of 1991–2020 at Dayton Mcd, OH, 7.5 miles away: half of years saw snow earlier, half later. Snow fell in 90% of those winters. The last 32°F night of spring typically comes 40 days after the last snow.

ZIP 45440 is 8 miles from Dayton Mcd, OH, which stands at 720 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 21 other ZIP codes share the station; its figures are presented in full for 45424 (Huber Heights). The 2023 USDA Plant Hardiness Zone Map lists ZIP 45440 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.