Frost Dates for 74075 — Stillwater, Oklahoma

Half of springs at Stillwater Regional Airport, OK see their last 32°F night by April 3; only one in ten is past it by March 18, and one in ten still has one after April 21. Planting tender crops after April 10 leaves a 30% risk of a frost on them, after April 15 20%, and after April 21 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 60% of the 114 Oklahoma stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 31 in half of years, as early as October 15 one year in ten, and holds off past November 14 one year in ten. A hard freeze of 28°F follows 8 days later, around November 8; in spring the one-in-ten date for 28°F is April 8, 13 days before the 32°F one. The freeze-free season lasts 209 days in a typical year, shorter than at 58% of the 114 Oklahoma stations; it reaches 231 days one year in ten and falls short of 187 one year in ten. On average 87 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 13 days longer, to about April 16, and return around October 22. Severe cold of 16°F or below comes in 99% of winters, usually between December 16 and February 17.

July is the warmest month at Stillwater Regional Airport, OK, averaging 95°F by day and 72°F at night; January is the coldest at 51°F and 27°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 59% of years.

Warmth for growing adds up to 5,389 growing degree days a year (base 50°F), more than at 84% of the 114 Oklahoma stations. 38% of them (2,050) have built up by the end of June, and July adds the most, 1,046. Precipitation totals 33.1 inches a year, most in May (4.6") and least in January (0.9"); May to September bring 56% of it.

The nearest other station, Stillwater 2 W, OK, 3 miles southwest of Stillwater, has a last frost 2 days later (April 5), a first frost 1 day earlier (October 30), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Stillwater usually arrives around December 12, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Stillwater 2 W, OK, 3 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 35 days after the last snow.

ZIP 74075 is 2 miles from Stillwater Regional Airport, OK, which stands at 984 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 74075 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.