Frost dates for Dayton, Ohio
In Dayton, half of springs have had their last frost by April 18 (and 1 spring in 10 still has one after May 5), and half of falls have had their first frost by October 25, leaving about 189 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Dayton, Ohio
Last spring frost
April 18
Half of springs have their last frost by this date. For a safer bet, wait until May 5: only 1 spring in 10 has a frost after that.
First fall frost
October 25
Half of falls have their first frost by this date. In 1 fall in 10 it comes by October 13.
Growing season
189 days
Frost-free days in a typical year. 9 years in 10 get at least 168.
Hardiness zone
6b
2023 USDA map: the coldest night of winter averages −5°F to 0°F. On the 2012 map it was 6a, half a zone colder. All 17 ZIP codes within about 6 miles of the city's center are in zone 6b.
Print a year planner for Dayton
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | April 3 | April 18 | May 5 |
| First frost in fall | October 13 | October 25 | November 7 |
The frost-free season between them runs 189 days in a typical year. In 1 year in 10 it is 209 days or longer, and in 1 year in 10 it is 168 days or shorter.
- Hard freeze (28°F): typically last on April 6 and first on November 4. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on April 30 and first on October 16. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Dayton comes between April 3 and May 5, a window of 32 days. That is about average for NOAA's stations (the typical window is 31 days).
Among Ohio's 130 NOAA stations with a frost every year, 84 percent have their typical last frost later than Dayton does.
Planting calendar for Dayton
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 31 to February 28 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| February | ||
| February 14 to March 14 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| February 28 to March 21 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| March | ||
| March 7 to 21 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| March 14 to 28 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| March 21 to April 4 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 21 to April 4 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| April | ||
| April 4 to 18 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| April 4 to 18 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| April 18 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| May | ||
| May 2 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| May 2 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| May 30 to June 13 | Cabbage for fall Start seeds | set the plants out by July 18 |
| June | ||
| June 19 to July 3 | Broccoli for fall Start seeds | set the plants out by August 7 |
| July | ||
| July 29 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August | ||
| August 2 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 3 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 7 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| August 8 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 12 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| August 22 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 1 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| September 11 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 13 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| November | ||
| November 11 to 18 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
Want more insurance? Shift every spring date 17 days later. That plans around May 5, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Dayton MCD (station USC00332067), 2 miles from the center of Dayton. It sits at about the same elevation, 720 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
The same station also gives the frost dates for Riverside.
Our ZIP code lookup matches these 25 ZIP codes to the same station, so they get the same dates: 45301, 45324, 45341, 45402, 45403, 45404, 45405, 45406, 45409, 45410, 45417, 45419, 45420, 45423, 45426, 45428, 45430, 45431, 45432, 45433, 45434, 45435, 45439, 45449, 45469. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- Cincinnati, Ohio: last frost around April 18, first frost around October 25 (45 miles away)
- Columbus, Ohio: last frost around April 18, first frost around October 27 (65 miles away)
- Fort Wayne, Indiana: last frost around April 24, first frost around October 21 (105 miles away)
See frost dates across Ohio, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.