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Frost dates and planting calendar for Oklahoma City, Oklahoma
- USDA hardiness zone
- 7b[1]
- Median last spring frost
- Apr 4[2]
- Median first fall frost
- Nov 2[3]
- Growing season, median
- 213 days[4]
Oklahoma City is in USDA hardiness zone 7b[1]. The median last spring frost at the Will Rogers Airport station is April 4[2].
Frost dates
These frost dates come from NOAA climate normals for the Oklahoma City Will Rogers Airport station, using records from 1991 to 2020[5]. In half of years the last spring frost comes after April 4, and in 1 of 10 years it comes after April 20[2]. In 9 of 10 years it comes after March 16[2]. The first fall frost comes before November 2 in half of years, and before October 21 in 1 of 10 years[3]. These are odds from past years and not a forecast, so any year can be earlier or later[5].
| Frost | Likely (9 in 10 years) | Even odds (5 in 10) | Unlikely (1 in 10) |
|---|---|---|---|
| Last spring frost (32°F)[2] | after March 16 | after April 4 | after April 20 |
| First fall frost (32°F)[3] | before October 21 | before November 2 | before November 17 |
- Hard freeze (28°F): median last spring date March 21, median first fall date November 11[7].
- Frost-free growing season: at least 191 days in 9 of 10 years, 213 days in half of years and 235 days in 1 of 10 years[4].
- The low reached 32°F or colder in 100% of years and 28°F or colder in 100% of years[8].
- Weather station: Oklahoma City Will Rogers Airport (USW00013967), 7.3 miles from the city center, 1,285 feet, 29 years of 1991 to 2020 records[5].
When to plant vegetables
The planting rules come from Colorado State University Extension, and its guide was written for Colorado[6]. GardenFacts used the NOAA median last frost of April 4 as the average last frost[6]. Hardy vegetables such as broccoli, lettuce, peas and spinach can go in as early as 2 to 4 weeks before that date, which is March 7 to March 21[6]. Semi-hardy vegetables such as beets, carrots and potatoes can go in as early as 2 weeks before it, from March 21 up to the median date[9]. Tender vegetables such as snap beans and sweet corn can be planted from seed around April 4[10]. Very tender vegetables such as tomatoes and peppers typically wait 2 or more weeks after it, so the earliest start is April 18[11].
- Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 4) is March 7 to March 21[6]
- Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 4) is March 21, up to the median date itself[9]
- Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 4[10]
- Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 4), is April 18[11]
| Vegetable (CSU group) | Plant from | First harvest around |
|---|---|---|
| Broccoli (hardy)[12] | Mar 7 | May 11 (from transplants) |
| Cabbage (hardy)[12] | Mar 7 | May 31 (from transplants) |
| Kohlrabi (hardy)[12] | Mar 7 | Apr 26 |
| Lettuce (hardy)[12] | Mar 7 | May 6 |
| Onions (hardy)[12] | Mar 7 | Jun 25 |
| Peas (hardy)[12] | Mar 7 | May 11 |
| Radishes (hardy)[12] | Mar 7 | Apr 6 |
| Spinach (hardy)[12] | Mar 7 | Apr 16 |
| Turnips (hardy)[12] | Mar 7 | Apr 26 |
| Beets (semi-hardy)[12] | Mar 21 | May 20 |
| Carrots (semi-hardy)[12] | Mar 21 | May 30 |
| Cauliflower (semi-hardy)[12] | Mar 21 | not listed |
| Parsnips (semi-hardy)[12] | Mar 21 | May 30 |
| Potatoes (semi-hardy)[12] | Mar 21 | Jul 24 |
| Swiss chard (semi-hardy)[12] | Mar 21 | May 20 |
| Snap beans (tender)[12] | Apr 4 | Jun 3 |
| Sweet corn (tender)[12] | Apr 4 | Jun 3 |
| Cucumbers (tender)[12] | Apr 4 | May 29 |
| Summer squash (tender)[12] | Apr 4 | May 24 |
| Cantaloupe (very tender)[12] | Apr 18 | Jul 12 |
| Eggplant (very tender)[12] | Apr 18 | Jun 17 (from transplants) |
| Peppers (very tender)[12] | Apr 18 | Jun 27 (from transplants) |
| Tomatoes (very tender)[12] | Apr 18 | Jun 22 (from transplants) |
| Winter squash (very tender)[12] | Apr 18 | Jul 27 |
| Watermelon (very tender)[12] | Apr 18 | Jul 12 |
Spacing, depth and soil temperature (CSU Extension)
| Vegetable | Min. soil temp | Depth | Spacing | Days to harvest |
|---|---|---|---|---|
| Broccoli[13] | 40°F | 1/2 in | 18 in | 65 |
| Cabbage[13] | 40°F | 1/2 in | 18 in | 85 |
| Kohlrabi[13] | 40°F | 1/2 in | 7-9 in | 50 |
| Lettuce[13] | 35°F | 1/4 in | 7-9 in | 60 |
| Onions[13] | 35°F | 1/4 in (seed), 1-2 in (sets) | 4-6 in | 110 |
| Peas[13] | 40°F | 1 in | 4-6 in | 65 |
| Radishes[13] | 40°F | 1/2 in | 2-3 in | 30 |
| Spinach[13] | 40°F | 1/2 in | 4-6 in | 40 |
| Turnips[13] | 40°F | 1/2 in | 4-6 in | 50 |
| Beets[13] | 40°F | 3/4-1 in | 4-6 in | 60 |
| Carrots[13] | 40°F | 1/4 in | 2-3 in | 70 |
| Cauliflower[13] | 40°F | 1/2 in | 18 in | – |
| Parsnips[13] | 35°F | 1/2 in | 5-6 in | 70 |
| Potatoes[13] | 45°F | – | – | 125 |
| Swiss chard[13] | 40°F | 1 in | 7-9 in | 60 |
| Snap beans[13] | 55°F | 1-1 1/2 in | 6 in | 60 |
| Sweet corn[13] | 50°F | 1-1 1/2 in | 12 x 30 in or 9 x 36 in | 60-90 |
| Cucumbers[13] | 60°F | 1 in | 6 in trellised, 24-36 in untrellised | 55 |
| Summer squash[13] | 60°F | 1-1 1/2 in | 36-48 in | 50 |
| Cantaloupe[13] | 60°F | 1-1 1/2 in | 36-48 in | 85 |
| Eggplant[13] | 60°F | 1/4 in | 18-24 in | 60 |
| Peppers[13] | 60°F | 1/4 in | 15-18 in | 70 |
| Tomatoes[13] | 50°F | 1/4 in | 24 in trellised | 65 |
| Winter squash[13] | 60°F | 1-1 1/2 in | 36-48 in | 100 |
| Watermelon[13] | 60°F | 1-1 1/2 in | 36-48 in | 85 |
Hardiness zone
Zone 7b means an average yearly coldest night of 5°F to 10°F over 1991 to 2020[1]. The zone is based on winter lows and not on summer heat or frost dates[14]. All of the city's land area lies in ZIP code areas rated zone 7b, so the city does not span more than one zone[15].
Zone 7b: average annual extreme minimum temperature 5°F to 10°F (1991 to 2020)[1]. Modeled value at the city center: 8.3°F[1].
Share of the city's land area by ZIP code zone: zone 7b 100%[15].
All towns in zone 7b and what zone 7b means
Zone by ZIP code
| ZIP code | Zone | Coldest night range |
|---|---|---|
| 73099[15] | 7b | 5 to 10°F |
| 73165[15] | 7b | 5 to 10°F |
| 73064[15] | 7b | 5 to 10°F |
| 74857[15] | 7b | 5 to 10°F |
| 73049[15] | 7b | 5 to 10°F |
| 73013[15] | 7b | 5 to 10°F |
| 73020[15] | 7b | 5 to 10°F |
| 73170[15] | 7b | 5 to 10°F |
| 73150[15] | 7b | 5 to 10°F |
| 73159[15] | 7b | 5 to 10°F |
| 73173[15] | 7b | 5 to 10°F |
| 73054[15] | 7b | 5 to 10°F |
| 73129[15] | 7b | 5 to 10°F |
| 73131[15] | 7b | 5 to 10°F |
| 73084[15] | 7b | 5 to 10°F |
| 73179[15] | 7b | 5 to 10°F |
| 73127[15] | 7b | 5 to 10°F |
| 73135[15] | 7b | 5 to 10°F |
| 73012[15] | 7b | 5 to 10°F |
| 73114[15] | 7b | 5 to 10°F |
| 73111[15] | 7b | 5 to 10°F |
| 73120[15] | 7b | 5 to 10°F |
| 73078[15] | 7b | 5 to 10°F |
| 73142[15] | 7b | 5 to 10°F |
| 73112[15] | 7b | 5 to 10°F |
| 73107[15] | 7b | 5 to 10°F |
| 73169[15] | 7b | 5 to 10°F |
| 73108[15] | 7b | 5 to 10°F |
| 73128[15] | 7b | 5 to 10°F |
| 73141[15] | 7b | 5 to 10°F |
Questions people ask
- What growing zone is Oklahoma City?
- Oklahoma City is in USDA zone 7b on the 2023 map[1]. All of its land area is in ZIP code areas rated 7b[15].
- When is the last frost in Oklahoma City?
- The median last spring frost is April 4[2]. In 1 of 10 years the last frost comes after April 20[2].
- When to plant tomatoes in Oklahoma City?
- CSU Extension says tomatoes typically go in 2 or more weeks after the average last spring frost[11]. Using the median frost of April 4, the earliest start is April 18[11].
Facts and sources
- The 2023 USDA Plant Hardiness Zone Map puts the center of Oklahoma City, Oklahoma in zone 7b. Zone 7b means an average annual extreme minimum temperature of 5°F to 10°F over 1991 to 2020. The map's modeled value at the city center is 8.3°F. USDA zone map 2023 (PRISM, OSU)
- Last spring frost (32°F) at this station: in 9 of 10 years the last frost comes after March 16, in half of years after April 4, and in 1 of 10 years after April 20 (NOAA 1991 to 2020 normals). The median last frost date is April 4. NOAA Climate Normals 1991-2020
- First fall frost (32°F) at this station: in 1 of 10 years the first frost comes before October 21, in half of years before November 2, and in 9 of 10 years before November 17 (NOAA 1991 to 2020 normals). The median first frost date is November 2. NOAA Climate Normals 1991-2020
- Growing season (days between the last spring and first fall 32°F frost) at this station: at least 191 days in 9 of 10 years, at least 213 days in half of years, and at least 235 days in 1 of 10 years. NOAA Climate Normals 1991-2020
- Frost dates on this page come from NOAA climate normals for the Oklahoma City Will Rogers Airport weather station (USW00013967), 7.3 miles from the center of Oklahoma City at 1,285 feet, using 29 years of records from 1991 to 2020. NOAA Climate Normals 1991-2020
- Colorado State University Extension's vegetable planting guide (written for Colorado) groups broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips as hardy vegetables, with this rule: as early as 2-4 weeks before the average last... CSU Extension GardenNotes #720
- Hard freeze (28°F) at this station: the median last spring date is March 21 and the median first fall date is November 11. NOAA Climate Normals 1991-2020
- At this station the low reached 32°F or colder in 100% of years from 1991 to 2020, and 28°F or colder in 100% of years. NOAA Climate Normals 1991-2020
- Colorado State University Extension's vegetable planting guide (written for Colorado) groups beets, carrots, cauliflower, parsnips, potatoes, Swiss chard as semi-hardy vegetables, with this rule: as early as 0-2 weeks before the average last spring frost.... CSU Extension GardenNotes #720
- Colorado State University Extension's vegetable planting guide (written for Colorado) groups snap beans, sweet corn, cucumbers, summer squash as tender vegetables, with this rule: from seed around the average last spring frost; cucumber and summer squash... CSU Extension GardenNotes #720
- Colorado State University Extension's vegetable planting guide (written for Colorado) groups cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon as very tender vegetables, with this rule: typically 2 or more weeks after the average last... CSU Extension GardenNotes #720
- GardenFacts calculation: earliest planting date plus CSU days to harvest (table on this page), from the station's median last frost. NOAA Climate Normals 1991-2020
- CSU Extension vegetable table: soil temperature, depth, spacing, days to harvest (table on this page). CSU Extension GardenNotes #720
- USDA hardiness zones are based on the average annual extreme minimum winter temperature (the coldest night of each winter, averaged over 1991 to 2020 for the 2023 map), not on summer heat or frost dates. Each zone spans 10°F and each half zone (a or b)... USDA Plant Hardiness Zone Map
- Oklahoma City, Oklahoma overlaps 40 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 7b. USDA zone map 2023 (PRISM, OSU)
Hardiness zone data: USDA Plant Hardiness Zone Map (2023), USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu, accessed October 30, 2026. This is not the official USDA map. Frost data: NOAA NCEI U.S. Climate Normals 1991-2020. Planting rules: Colorado State University Extension.