Frost Dates for 73717 — Alva, Oklahoma

Half of springs at Alva 1W, OK see their last 32°F night by April 10; only one in ten is past it by March 26, and one in ten still has one after April 25. Planting tender crops after April 16 leaves a 30% risk of a frost on them, after April 20 20%, and after April 25 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 86% of the 114 Oklahoma stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 28 in half of years, as early as October 14 one year in ten, and holds off past November 10 one year in ten. A hard freeze of 28°F follows 8 days later, around November 5; in spring the one-in-ten date for 28°F is April 14, 11 days before the 32°F one. The freeze-free season lasts 199 days in a typical year, shorter than at 86% of the 114 Oklahoma stations; it reaches 221 days one year in ten and falls short of 181 one year in ten. On average 106 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 April 20, and return around October 18. Severe cold of 16°F or below comes every winter, usually between December 3 and February 24.

July is the warmest month at Alva 1W, OK, averaging 95°F by day and 71°F at night; January is the coldest at 47°F and 23°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 81% of years.

Warmth for growing adds up to 4,807 growing degree days a year (base 50°F), fewer than at 86% of the 114 Oklahoma stations. 37% of them (1,761) have built up by the end of June, and July adds the most, 1,018. Precipitation totals 30.3 inches a year, most in June (4.5") and least in January (1.0"); May to September bring 58% of it.

The nearest other station, Medicine Lodge, KS, 34 miles north of Alva, has a last frost 3 days later (April 13), a first frost 5 days earlier (October 23), a season 8 days shorter.

The first measurable snow (0.1 inch or more) in Alva usually arrives around December 16, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Alva 1W, OK, 0.6 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 42 days after the last snow.

ZIP 73717 is under a mile from Alva 1W, OK, which stands at 1,464 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 73717 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.