Cincinnati, Ohio: planting zone & frost dates
Cincinnati is in USDA plant hardiness zone 6b, where the average coldest winter night reaches -5 to 0°F (-20.6 to -17.8°C). The typical last spring frost is around Apr 24 and the first fall frost around Oct 21.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 5 | Oct 11 |
| Typical planning date (30% risk) | Apr 24 | Oct 21 |
| Median (50%) | Apr 17 | Oct 26 |
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 CHEVIOT, OH (USC00331515), 6.4 mi (10.3 km) from the city center and 131 ft higher than the city center (+40 m). Record used for the 1991–2020 normals: 26 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Cincinnati
All 27 ZIP codes covering Cincinnati are in zone 6b.
ZIP codes in Cincinnati and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 45226 | 6b | 6.7% |
| 45230 | 6b | 6.7% |
| 45211 | 6b | 6.2% |
| 45223 | 6b | 6.0% |
| 45208 | 6b | 5.5% |
| 45232 | 6b | 5.2% |
| 45224 | 6b | 4.9% |
| 45238 | 6b | 4.5% |
| 45237 | 6b | 3.9% |
| 45225 | 6b | 3.8% |
| 45204 | 6b | 3.7% |
| 45220 | 6b | 3.7% |
| 45205 | 6b | 3.5% |
| 45229 | 6b | 3.5% |
| 45202 | 6b | 3.4% |
| 45214 | 6b | 3.4% |
| 45227 | 6b | 3.0% |
| 45213 | 6b | 2.8% |
| 45209 | 6b | 2.7% |
| 45233 | 6b | 2.7% |
| 45206 | 6b | 2.6% |
| 45216 | 6b | 2.5% |
| 45219 | 6b | 2.0% |
| 45203 | 6b | 1.5% |
| 45207 | 6b | 1.5% |
| 45239 | 6b | 1.5% |
| 45267 | 6b | 0.1% |
Vegetable planting calendar for Cincinnati
Dates are counted from the 30%-risk frost dates above (last frost Apr 24, first frost Oct 21). 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 27 – Mar 13 | May 1 – May 15 | — | — |
| Pepper | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Lettuce | Mar 13 – Mar 27 | Apr 10 – May 1 | Mar 27 – May 8 | Aug 12 – Sep 9 |
| Green Beans | — | — | May 1 – Jun 5 | Jul 29 – Aug 12 |
| Sweet Corn | — | — | May 1 – May 29 | — |
| Zucchini & Summer Squash | Mar 27 – Apr 3 | May 1 – May 15 | May 1 – May 22 | Jul 29 – Aug 12 |
| Cucumber | Mar 27 – Apr 3 | May 8 – May 15 | May 1 – May 22 | Jul 29 – Aug 12 |
| Carrot | — | — | Apr 3 – May 8 | Jul 29 – Aug 12 |
| Onion | Jan 30 – Feb 13 | Mar 27 – Apr 10 | — | — |
| Potato | — | Mar 27 – Apr 17 | — | — |
| Basil | Mar 13 – Mar 27 | May 8 – May 22 | May 8 – May 29 | — |
| Spinach | — | — | Mar 13 – Apr 10 | Aug 26 – Sep 23 |
| Kale | Feb 27 – Mar 13 | Mar 27 – Apr 17 | Mar 27 – Apr 17 | Aug 12 – Sep 9 |
| Broccoli | Feb 27 – Mar 13 | Apr 10 – May 1 | — | Jul 29 – Aug 12 |
| Peas | — | — | Mar 13 – Apr 3 | Aug 12 – Aug 26 |
| Eggplant | Feb 13 – Feb 27 | May 8 – May 22 | — | — |
| Cabbage | Feb 27 – Mar 13 | Mar 27 – Apr 10 | — | Jul 29 – Aug 12 |
| Radish | — | — | Mar 20 – May 8 | Sep 9 – Oct 7 |
| Strawberry | — | Mar 27 – Apr 17 | — | — |
| Beets | — | — | Apr 3 – May 15 | Aug 12 – Aug 26 |
Nearby cities in Ohio
- Dayton — zone 6b, last frost Apr 25, first frost Oct 21
- Columbus — zone 6b, last frost Apr 27, first frost Oct 20
- Toledo — zone 6b, last frost Apr 27, first frost Oct 22
- Akron — zone 6b, last frost Apr 30, first frost Oct 22
- Parma — zone 6b, last frost Apr 27, first frost Oct 30
- Cleveland — zone 7a, last frost Apr 14, first frost Nov 7
More: all Ohio cities · other zone 6b cities: Columbus, OH, Indianapolis, IN, Boston, MA, Detroit, MI, Kansas City, MO, Pittsburgh, PA, Buffalo, NY, Toledo, OH
Cincinnati gardening questions
When is the last frost in Cincinnati, OH?
Plan around Apr 24. At NOAA's Cheviot, OH station, 6.4 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 17, and after May 5 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 4. The 90% and 10% dates are 33 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Cincinnati, OH?
Start seeds indoors Feb 27 – Mar 13 and set transplants outside May 1 – May 15, once nights stay above 50°F and the soil is near 60°F. That leaves 180 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 Cincinnati?
About 191 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 168 days, and in 1 year in 10 it runs 211 days or more. In fall there is a 10% chance of frost by Oct 11 and a 30% chance by Oct 21. That ranks 3rd longest of 7 Ohio cities on this site.
When should I plant a fall garden in Cincinnati?
Count back from the first fall frost (Oct 21): transplant broccoli Jul 29 – Aug 12; sow kale Aug 12 – Sep 9; sow lettuce Aug 12 – Sep 9; sow radishes Sep 9 – Oct 7. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 4. How the math works: succession and fall planting.
Did Cincinnati's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Cincinnati is zone 6b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Cincinnati compare with Dayton, OH?
Both are in zone 6b. The typical last spring frost in Cincinnati (Apr 24) comes about the same time as in Dayton, OH (Apr 25), 47 miles away, and the first fall frost is Oct 21 versus Oct 21. The two cities use different NOAA stations.