USDA Hardiness Zone 7b
Frost Dates for 73120 — Oklahoma City, Oklahoma
NOAA 1991–2020 normals from Oklahoma City Post Airport, OK (1,297 ft), 6 miles southwest.
Updated
In Oklahoma City, the last spring frost (32°F) is around April 2 in half of years and has passed by April 18 in nine years out of ten. The first fall frost comes around November 4, as early as October 21 one year in ten, leaving a typical freeze-free season of 216 days (NOAA, Oklahoma City Post Airport, OK).
- Last spring frost
- April 2
- First fall frost
- November 4
- Growing season
- 216 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- December 19
- Last snow
- February 17
- Winters with snow
- 100%
- Snow per year
- 6.7"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Oklahoma City
Half of springs at Oklahoma City Post Airport, OK see their last 32°F night by April 2; only one in ten is past it by March 14, and one in ten still has one after April 18. Planting tender crops after April 8 leaves a 30% risk of a frost on them, after April 11 20%, and after April 18 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 61% 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 18 one year in ten. A hard freeze of 28°F follows 9 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 239 days one year in ten and falls short of 194 one year in ten. On average 73 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 13, and return around October 27. Severe cold of 16°F or below comes in 99% of winters, usually between December 20 and February 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 30 | Apr 3 | Apr 7 | Apr 9 | Apr 13 | Apr 16 | Apr 19 | Apr 23 | Apr 29 |
| 32°F | Mar 14 | Mar 21 | Mar 27 | Mar 30 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 18 |
| 28°F | Feb 28 | Mar 6 | Mar 11 | Mar 14 | Mar 19 | Mar 23 | Mar 28 | Mar 31 | Apr 5 |
| 24°F | Feb 19 | Feb 24 | Feb 28 | Mar 4 | Mar 8 | Mar 11 | Mar 15 | Mar 20 | Mar 27 |
| 20°F | Jan 31 | Feb 13 | Feb 19 | Feb 23 | Feb 27 | Mar 2 | Mar 5 | Mar 9 | Mar 15 |
| 16°F99% of yrs | Jan 16 | Jan 27 | Feb 1 | Feb 8 | Feb 14 | Feb 20 | Feb 25 | Mar 2 | Mar 7 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 9 |
| 32°F | Oct 21 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 6 | Nov 10 | Nov 13 | Nov 18 |
| 28°F | Oct 31 | Nov 3 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 30 |
| 24°F | Nov 5 | Nov 11 | Nov 15 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 4 | Dec 10 |
| 20°F | Nov 14 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 8 | Dec 13 | Dec 19 | Dec 27 |
| 16°F99% of yrs | Nov 25 | Dec 2 | Dec 7 | Dec 13 | Dec 20 | Dec 25 | Jan 1 | Jan 7 | Jan 17 |
Freeze probabilities 1991–2020 at Oklahoma City Post Airport, OK, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 73120 →Compare Oklahoma City with another place →
Weather by month in Oklahoma City
July is the warmest month at Oklahoma City Post Airport, OK, averaging 95°F by day and 73°F at night; January is the coldest at 51°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 55% of years.
Warmth for growing adds up to 5,363 growing degree days a year (base 50°F), more than at 81% of the 114 Oklahoma stations. 38% of them (2,029) have built up by the end of June, and July adds the most, 1,051. Precipitation totals 30.8 inches a year, most in June (4.8") and least in January (0.8"); May to September bring 60% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 51 | 28 | 0.8 | 100% | 22 | 20 |
| Feb | 55 | 31 | 1.0 | 100% | 16 | 46 |
| Mar | 64 | 40 | 2.0 | 95% | 7 | 164 |
| Apr | 72 | 49 | 3.0 | 55% | 1 | 330 |
| May | 80 | 59 | 4.3 | 0% | 0 | 613 |
| Jun | 89 | 68 | 4.8 | 0% | 0 | 856 |
| Jul | 95 | 73 | 2.9 | 0% | 0 | 1051 |
| Aug | 94 | 71 | 3.5 | 0% | 0 | 1006 |
| Sep | 85 | 63 | 3.0 | 0% | 0 | 728 |
| Oct | 74 | 51 | 2.7 | 35% | 1 | 397 |
| Nov | 62 | 39 | 1.5 | 99% | 8 | 126 |
| Dec | 51 | 30 | 1.3 | 100% | 19 | 28 |
Monthly normals 1991–2020 at Oklahoma City Post Airport, OK (1,297 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Spencer 2ENE Mesonet, OK, 13 miles east of Oklahoma City, has the same 50% last-frost date, a first frost 1 day later (November 5), a season 1 day longer.
When it snows in Oklahoma City, Oklahoma
The first measurable snow (0.1 inch or more) in Oklahoma City usually arrives around December 19, and the last of the season around February 17. Those are the middle dates across the winters of 1991–2020 at Oklahoma City Will Rogers Airport, OK, 13.3 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 44 days after the last snow.
Planting calendar for 73120
| When | What to do |
|---|---|
| January 22 – February 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 5 – February 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 5 – March 19 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 2 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 12 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 21 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 4 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 73120 is 6 miles from Oklahoma City Post Airport, OK, which stands at 1,297 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 17 other ZIP codes share the station; its figures are presented in full for 73099 (Yukon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 73120 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.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.