Frost Dates for 73742 — Hennessey, Oklahoma

Half of springs at Hennessey 4 ESE, OK see their last 32°F night by April 14; only one in ten is past it by March 29, and one in ten still has one after April 27. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 23 20%, and after April 27 10%. The 13 days between the even-odds date and the one-in-ten date is the narrowest of the 114 Oklahoma stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 30 in half of years, as early as October 17 one year in ten, and holds off past November 11 one year in ten. A hard freeze of 28°F follows 7 days later, around November 6; in spring the one-in-ten date for 28°F is April 18, 9 days before the 32°F one. The freeze-free season lasts 198 days in a typical year, shorter than at 89% of the 114 Oklahoma stations; it reaches 220 days one year in ten and falls short of 178 one year in ten. On average 94 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 April 23, and return around October 21. Severe cold of 16°F or below comes every winter, usually between December 6 and February 25.

July is the warmest month at Hennessey 4 ESE, OK, averaging 95°F by day and 70°F at night; January is the coldest at 47°F and 24°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 84% of years.

Warmth for growing adds up to 4,778 growing degree days a year (base 50°F), fewer than at 89% of the 114 Oklahoma stations. 36% of them (1,718) have built up by the end of June, and July adds the most, 1,006. Precipitation totals 33.4 inches a year, most in May (5.0") and least in January (1.3"); May to September bring 55% of it.

The nearest other station, Marshall 3SSE Mesonet, OK, 15 miles east of Hennessey and 154 feet lower, has a last frost 3 days earlier (April 11), a first frost 1 day later (October 31), a season 3 days longer.

The first measurable snow (0.1 inch or more) in Hennessey usually arrives around December 11, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Hennessey 4 ESE, OK, 2.8 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 47 days after the last snow.

ZIP 73742 is 3 miles from Hennessey 4 ESE, OK, which stands at 1,174 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 73742 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.