Dayton, Ohio: planting zone & frost dates
Dayton 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 25 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 13 |
| Typical planning date (30% risk) | Apr 25 | Oct 21 |
| Median (50%) | Apr 18 | Oct 25 |
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 DAYTON MCD, OH (USC00332067), 1.6 mi (2.5 km) from the city center and 30 ft lower than the city center (-9 m). Record used for the 1991–2020 normals: 28 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Dayton
All 16 ZIP codes covering Dayton are in zone 6b.
Vegetable planting calendar for Dayton
Dates are counted from the 30%-risk frost dates above (last frost Apr 25, 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 28 – Mar 14 | May 2 – May 16 | — | — |
| Pepper | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Lettuce | Mar 14 – Mar 28 | Apr 11 – May 2 | Mar 28 – May 9 | Aug 12 – Sep 9 |
| Green Beans | — | — | May 2 – Jun 6 | Jul 29 – Aug 12 |
| Sweet Corn | — | — | May 2 – May 30 | — |
| Zucchini & Summer Squash | Mar 28 – Apr 4 | May 2 – May 16 | May 2 – May 23 | Jul 29 – Aug 12 |
| Cucumber | Mar 28 – Apr 4 | May 9 – May 16 | May 2 – May 23 | Jul 29 – Aug 12 |
| Carrot | — | — | Apr 4 – May 9 | Jul 29 – Aug 12 |
| Onion | Jan 31 – Feb 14 | Mar 28 – Apr 11 | — | — |
| Potato | — | Mar 28 – Apr 18 | — | — |
| Basil | Mar 14 – Mar 28 | May 9 – May 23 | May 9 – May 30 | — |
| Spinach | — | — | Mar 14 – Apr 11 | Aug 26 – Sep 23 |
| Kale | Feb 28 – Mar 14 | Mar 28 – Apr 18 | Mar 28 – Apr 18 | Aug 12 – Sep 9 |
| Broccoli | Feb 28 – Mar 14 | Apr 11 – May 2 | — | Jul 29 – Aug 12 |
| Peas | — | — | Mar 14 – Apr 4 | Aug 12 – Aug 26 |
| Eggplant | Feb 14 – Feb 28 | May 9 – May 23 | — | — |
| Cabbage | Feb 28 – Mar 14 | Mar 28 – Apr 11 | — | Jul 29 – Aug 12 |
| Radish | — | — | Mar 21 – May 9 | Sep 9 – Oct 7 |
| Strawberry | — | Mar 28 – Apr 18 | — | — |
| Beets | — | — | Apr 4 – May 16 | Aug 12 – Aug 26 |
Nearby cities in Ohio
- Cincinnati — zone 6b, last frost Apr 24, 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
- Parma — zone 6b, last frost Apr 27, first frost Oct 30
- Akron — zone 6b, last frost Apr 30, first frost Oct 22
- 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, Cincinnati, OH, Pittsburgh, PA, Buffalo, NY
Dayton gardening questions
When is the last frost in Dayton, OH?
Plan around Apr 25. At NOAA's Dayton Mcd, OH station, 1.6 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 18, and after May 5 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 6. The 90% and 10% dates are 32 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Dayton, OH?
Start seeds indoors Feb 28 – Mar 14 and set transplants outside May 2 – May 16, once nights stay above 50°F and the soil is near 60°F. That leaves 179 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 Dayton?
About 189 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 209 days or more. In fall there is a 10% chance of frost by Oct 13 and a 30% chance by Oct 21. That ranks 4th longest of 7 Ohio cities on this site.
When should I plant a fall garden in Dayton?
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 Dayton's hardiness zone change on the 2023 map?
Yes. Most of Dayton was zone 6a on the 2012 map and is zone 6b 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 Dayton compare with Cincinnati, OH?
Both are in zone 6b. The typical last spring frost in Dayton (Apr 25) comes about the same time as in Cincinnati, OH (Apr 24), 47 miles away, and the first fall frost is Oct 21 versus Oct 21. The two cities use different NOAA stations.