Frost Dates for 74547 — Hartshorne, Oklahoma

Half of springs at Mcalester Regional Airport, OK see their last 32°F night by March 31; only one in ten is past it by March 11, and one in ten still has one after April 18. Planting tender crops after April 6 leaves a 30% risk of a frost on them, after April 11 20%, and after April 18 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 November 3 in half of years, as early as October 20 one year in ten, and holds off past November 19 one year in ten. A hard freeze of 28°F follows 10 days later, around November 13; in spring the one-in-ten date for 28°F is April 5, 13 days before the 32°F one. The freeze-free season lasts 216 days in a typical year, longer than at 65% of the 114 Oklahoma stations; it reaches 241 days one year in ten and falls short of 193 one year in ten. On average 66 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 11 days longer, to about April 11, and return around October 26. Severe cold of 16°F or below comes in 93% of winters, usually between December 25 and February 3.

July is the warmest month at Mcalester Regional Airport, OK, averaging 93°F by day and 72°F at night; January is the coldest at 52°F and 30°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 47% of years.

Warmth for growing adds up to 5,478 growing degree days a year (base 50°F), more than at 89% of the 114 Oklahoma stations. 39% of them (2,119) have built up by the end of June, and July adds the most, 1,011. Precipitation totals 42.7 inches a year, most in May (5.3") and least in January (2.2"); May to September bring 47% of it.

The nearest other station, Tuskahoma, OK, 23 miles southeast of Hartshorne and 170 feet lower, has a last frost 11 days later (April 11), a first frost 7 days earlier (October 27), a season 17 days shorter.

Measurable snow is rare here: only 5 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Clayton 14 WNW, OK, 12.6 miles away, so there is no typical first-snow date to plan around.

ZIP 74547 is 12 miles from Mcalester Regional Airport, OK, which stands at 770 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 74501 (Mcalester). The 2023 USDA Plant Hardiness Zone Map lists ZIP 74547 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.