Frost Dates for 42327 — Calhoun, Kentucky

Half of springs at Calhoun Lock 2, KY see their last 32°F night by April 2; only one in ten is past it by March 17, and one in ten still has one after April 20. Planting tender crops after April 10 leaves a 30% risk of a frost on them, after April 14 20%, and after April 20 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 54% of the 113 Kentucky stations behind this site's ZIP pages.

In fall the first 32°F night comes by November 1 in half of years, as early as October 19 one year in ten, and holds off past November 15 one year in ten. A hard freeze of 28°F follows 9 days later, around November 10; in spring the one-in-ten date for 28°F is April 10, 10 days before the 32°F one. The freeze-free season lasts 211 days in a typical year, longer than at 90% of the 113 Kentucky stations; it reaches 234 days one year in ten and falls short of 191 one year in ten. On average 83 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 14, and return around October 23. Severe cold of 16°F or below comes in 99% of winters, usually between December 20 and February 11.

July is the warmest month at Calhoun Lock 2, KY, averaging 87°F by day and 68°F at night; January is the coldest at 43°F and 26°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 55% of years.

Warmth for growing adds up to 4,293 growing degree days a year (base 50°F), more than at 74% of the 113 Kentucky stations. 38% of them (1,637) have built up by the end of June, and July adds the most, 852. Precipitation totals 45.7 inches a year, most in May (4.6") and least in August (2.9"); May to September bring 41% of it.

The nearest other station, Madisonville, KY, 20 miles southwest of Calhoun, has the same 50% last-frost date, the same first-frost date, a season 1 day longer.

The first measurable snow (0.1 inch or more) in Calhoun usually arrives around January 12, and the last of the season around February 9. Those are the middle dates across the winters of 1991–2020 at Calhoun Lock 2, KY, 3.4 miles away: half of years saw snow earlier, half later. Snow fell in 75% of those winters. The last 32°F night of spring typically comes 52 days after the last snow.

ZIP 42327 is 3 miles from Calhoun Lock 2, KY, which stands at 402 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 42301 (Owensboro). The 2023 USDA Plant Hardiness Zone Map lists ZIP 42327 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.