Frost dates for Tulsa, Oklahoma

Oklahoma · first & last freeze, from NOAA 1991–2020 climate normals

Typical last spring freeze (32°F)

March 31

median date, 1991–2020

Typical first fall freeze (32°F)

November 4

median date, 1991–2020

Typical frost-free season

218 days

between the median dates

In a typical year, the last spring freeze around Tulsa comes near March 31 and the first fall freeze near November 4. One year in ten, a freeze still arrives after April 15 in spring — and one year in ten, the first fall freeze has already landed by October 20. NCEI's own growing-season statistic (days between freezes, percentiled per year) puts the median at 220 days.

The year at a glance: blue bands span the 9-in-10 to 1-in-10 range where the last spring / first fall 32°F freeze lands; the green band is the typical frost-free window between the median dates. Measured at Tulsa Intl Ap, OK (USW00013968), 5.0 mi from the city's census reference point, elev. 650 ft. NOAA/NCEI 1991–2020 normals.

Freeze-date probabilities, three thresholds

Threshold	Last spring — 9 in 10 years past by	Last spring — typical (median)	Last spring — 1 in 10 years later than	First fall — 1 in 10 years by	First fall — typical (median)	First fall — 9 in 10 years by
36°F — near-freezing (frost can occur)	March 26	April 10	April 27	October 11	October 26	November 6
32°F — freezing	March 11	March 31	April 15	October 20	November 4	November 19
28°F — hard freeze	February 28	March 17	April 5	October 31	November 13	December 1

Measured at Tulsa Intl Ap, OK (USW00013968), 5.0 mi from the city's census reference point, elev. 650 ft. NOAA/NCEI 1991–2020 normals. Read each date column as odds over the 30-year record — e.g. "9 in 10 years past by" means only one spring in ten saw a later freeze than that date.

Frost-free windows (computed)

Window (32°F ends)	Opens	Closes	Length
Cautious (1-in-10 freeze risk at each end)	April 15	October 20	188 days
Typical (median freeze dates)	March 31	November 4	218 days
Gambler's (9-in-10 freeze risk at each end)	March 11	November 19	253 days

Pure arithmetic on the freeze-date percentiles above — the "cautious" window opens on the date only 1 year in 10 still sees a later spring freeze, and closes on the date by which only 1 year in 10 has already frozen.

About this city's numbers

Census entity: Tulsa city, Oklahoma — official 2024 population estimate 415,154.
Weather station: Tulsa Intl Ap, OK (USW00013968), 5.0 mi from the city's census-gazetteer reference point at elevation 650 ft. Frost dates are that station's history — neighborhoods vary.
Data pulled 2026-09-05; normals period 1991-2020 (replaced by NOAA roughly once a decade).

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