Norman, Oklahoma: planting zone & frost dates
Norman is in USDA plant hardiness zone 7b, where the average coldest winter night reaches 5 to 10°F (-15.0 to -12.2°C). The typical last spring frost is around Apr 9 and the first fall frost around Oct 29.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 18 | Oct 21 |
| Typical planning date (30% risk) | Apr 9 | Oct 29 |
| Median (50%) | Apr 3 | Nov 3 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station NORMAN 3SSE, OK (USC00346386), 6.6 mi (10.7 km) from the city center and 7 ft lower than the city center (-2 m). Record used for the 1991–2020 normals: 20 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Norman
All 8 ZIP codes covering Norman are in zone 7b.
Vegetable planting calendar for Norman
Dates are counted from the 30%-risk frost dates above (last frost Apr 9, first frost Oct 29). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 12 – Feb 26 | Apr 16 – Apr 30 | — | — |
| Pepper | Jan 29 – Feb 12 | Apr 23 – May 7 | — | — |
| Lettuce | Feb 26 – Mar 12 | Mar 26 – Apr 16 | Mar 12 – Apr 23 | Aug 20 – Sep 17 |
| Green Beans | — | — | Apr 16 – May 21 | Aug 6 – Aug 20 |
| Sweet Corn | — | — | Apr 16 – May 14 | — |
| Zucchini & Summer Squash | Mar 12 – Mar 19 | Apr 16 – Apr 30 | Apr 16 – May 7 | Aug 6 – Aug 20 |
| Cucumber | Mar 12 – Mar 19 | Apr 23 – Apr 30 | Apr 16 – May 7 | Aug 6 – Aug 20 |
| Carrot | — | — | Mar 19 – Apr 23 | Aug 6 – Aug 20 |
| Onion | Jan 15 – Jan 29 | Mar 12 – Mar 26 | — | — |
| Potato | — | Mar 12 – Apr 2 | — | — |
| Basil | Feb 26 – Mar 12 | Apr 23 – May 7 | Apr 23 – May 14 | — |
| Spinach | — | — | Feb 26 – Mar 26 | Sep 3 – Oct 1 |
| Kale | Feb 12 – Feb 26 | Mar 12 – Apr 2 | Mar 12 – Apr 2 | Aug 20 – Sep 17 |
| Broccoli | Feb 12 – Feb 26 | Mar 26 – Apr 16 | — | Aug 6 – Aug 20 |
| Peas | — | — | Feb 26 – Mar 19 | Aug 20 – Sep 3 |
| Eggplant | Jan 29 – Feb 12 | Apr 23 – May 7 | — | — |
| Cabbage | Feb 12 – Feb 26 | Mar 12 – Mar 26 | — | Aug 6 – Aug 20 |
| Radish | — | — | Mar 5 – Apr 23 | Sep 17 – Oct 15 |
| Strawberry | — | Mar 12 – Apr 2 | — | — |
| Beets | — | — | Mar 19 – Apr 30 | Aug 20 – Sep 3 |
Nearby cities in Oklahoma
- Oklahoma City — zone 7b, last frost Apr 10, first frost Oct 29
- Edmond — zone 7b, last frost Apr 18, first frost Oct 23
- Lawton — zone 7b, last frost Apr 3, first frost Nov 1
- Tulsa — zone 7b, last frost Apr 5, first frost Oct 30
- Broken Arrow — zone 7b, last frost Apr 8, first frost Oct 26
More: all Oklahoma cities · other zone 7b cities: New York, NY, Philadelphia, PA, Oklahoma City, OK, Nashville, TN, Washington, DC, Baltimore, MD, Albuquerque, NM, Tulsa, OK
Norman gardening questions
When is the last frost in Norman, OK?
Plan around Apr 9. At NOAA's Norman 3SSE, OK station, 6.6 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 3, and after Apr 18 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Mar 23. The 90% and 10% dates are 30 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Norman, OK?
Start seeds indoors Feb 12 – Feb 26 and set transplants outside Apr 16 – Apr 30, once nights stay above 50°F and the soil is near 60°F. That leaves 203 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Norman?
About 212 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 191 days, and in 1 year in 10 it runs 234 days or more. In fall there is a 10% chance of frost by Oct 21 and a 30% chance by Oct 29. That ranks 4th longest of 6 Oklahoma cities on this site.
When should I plant a fall garden in Norman?
Count back from the first fall frost (Oct 29): transplant broccoli Aug 6 – Aug 20; sow kale Aug 20 – Sep 17; sow lettuce Aug 20 – Sep 17; sow radishes Sep 17 – Oct 15. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 12. How the math works: succession and fall planting.
Did Norman's hardiness zone change on the 2023 map?
Yes. Most of Norman was zone 7a on the 2012 map and is zone 7b on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Norman compare with Oklahoma City, OK?
Both are in zone 7b. The typical last spring frost in Norman (Apr 9) comes about the same time as in Oklahoma City, OK (Apr 10), 18 miles away, and the first fall frost is Oct 29 versus Oct 29. The two cities use different NOAA stations.