Frost Dates for 74136 — Tulsa, Oklahoma

Half of springs at Tulsa R L Jones Jr Airport, OK see their last 32°F night by March 30; only one in ten is past it by March 10, and one in ten still has one after April 17. Planting tender crops after April 5 leaves a 30% risk of a frost on them, after April 9 20%, and after April 17 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 4 in half of years, as early as October 21 one year in ten, and holds off past November 20 one year in ten. A hard freeze of 28°F follows 10 days later, around November 14; in spring the one-in-ten date for 28°F is April 3, 14 days before the 32°F one. The freeze-free season lasts 220 days in a typical year, longer than at 77% of the 114 Oklahoma stations; it reaches 243 days one year in ten and falls short of 195 one year in ten. On average 81 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 9, and return around October 26. Severe cold of 16°F or below comes in 96% of winters, usually between December 24 and February 6.

July is the warmest month at Tulsa R L Jones Jr Airport, OK, averaging 94°F by day and 73°F at night; January is the coldest at 50°F and 28°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 45% of years.

Warmth for growing adds up to 5,363 growing degree days a year (base 50°F), more than at 82% of the 114 Oklahoma stations. 39% of them (2,067) have built up by the end of June, and July adds the most, 1,031. Precipitation totals 42.0 inches a year, most in May (6.1") and least in January (1.6"); May to September bring 52% of it.

The nearest other station, Bixby, OK, 6 miles southeast of Tulsa, has a last frost 2 days later (April 1), a first frost 3 days earlier (November 1), a season 8 days shorter.

The first measurable snow (0.1 inch or more) in Tulsa usually arrives around December 10, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Tulsa International Airport, OK, 10.1 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 31 days after the last snow.

ZIP 74136 is 3 miles from Tulsa R L Jones Jr Airport, OK, which stands at 638 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 13 other ZIP codes share the station; its figures are presented in full for 74066 (Sapulpa). The 2023 USDA Plant Hardiness Zone Map lists ZIP 74136 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.