Frost dates Ohio Cincinnati

Frost dates in Cincinnati, Ohio

Last spring frost Apr 16 First fall frost Oct 25 NOAA 1991-2020

The average last spring frost in Cincinnati is Apr 16 and the average first fall frost is Oct 25, measured at CINCINNATI LUNKEN AP, about 5 miles from the city centre. Below: how sure those dates are, and what to start, sow and set out each week.

Average last spring frostApr 1632°F, 50% probability
Average first fall frostOct 2532°F, 50% probability
Days between them192average frost-free season
How sure is that date? NOAA probability levels for a 32°F freeze
ProbabilityFreeze still comes after (spring)First freeze has come by (fall)
90%Apr 2Nov 5
50%Apr 16Oct 25
10%May 3Oct 12

Read it like this: in half of years the last 32°F freeze of spring comes after Apr 16, and in 1 year in 10 there is still a freeze after May 3. In 1 year in 10 the first fall freeze arrives before Oct 12.

Measured at: CINCINNATI LUNKEN AP, OH (NOAA station USW00093812), about 5 miles away at 490 ft, 29 years of record in 1991-2020.

Other stations nearby, for comparison:

  • CHEVIOT, OH (NOAA station USC00331515), about 6 miles away at 891 ft, 26 years of record in 1991-2020: last spring frost Apr 17, first fall frost Oct 26
  • CINCINNATI-FERNBANK, OH (NOAA station USC00331550), about 10 miles away at 500 ft, 19 years of record in 1991-2020: last spring frost Apr 13, first fall frost Oct 31

Seed-starting schedule for Cincinnati, OH

Counted from a last frost date of Apr 16 (the average: a freeze comes later than this in half of years).

  1. Week of Jan 814 weeks before last frost
    • Start seeds indoorsLeekJan 8 to Jan 22
    • Start seeds indoorsOnionJan 8 to Jan 22
  2. Week of Jan 1513 weeks before last frost
    • Start seeds indoorsParsleyJan 15 to Jan 22
  3. Week of Jan 2212 weeks before last frost
    • Start seeds indoorsCeleryJan 22 to Feb 5
    • Start seeds indoorsSpinachJan 22 to Feb 5
  4. Week of Feb 510 weeks before last frost
    • Start seeds indoorsBroccoliFeb 5 to Feb 19
    • Start seeds indoorsBrussels sproutFeb 5 to Feb 19
    • Start seeds indoorsCabbageFeb 5 to Feb 19
    • Start seeds indoorsKaleFeb 5 to Feb 19
    • Start seeds indoorsKohlrabiFeb 5 to Feb 19
  5. Week of Feb 129 weeks before last frost
    • Start seeds indoorsLettuceFeb 12 to Feb 19
  6. Week of Feb 198 weeks before last frost
    • Start seeds indoorsCauliflowerFeb 19 to Mar 5
    • Start seeds indoorsEggplantFeb 19 to Mar 5
    • Start seeds indoorsPepperFeb 19 to Mar 5
    • Start seeds indoorsSwiss chardFeb 19 to Mar 5
  7. Week of Feb 267 weeks before last frost
    • Start seeds indoorsTomatoFeb 26 to Mar 12
  8. Week of Mar 56 weeks before last frost
    • Start seeds indoorsBasilMar 5 to Mar 19
    • Set transplants outSpinachMar 5 to Mar 26
  9. Week of Mar 194 weeks before last frost
    • Sow seed outdoorsRadishMar 19 to Apr 2
    • Sow seed outdoorsSwiss chardfrom Mar 19
    • Sow seed outdoorsTurnipMar 19 to Apr 2
    • Set transplants outBroccoliMar 19 to Apr 2
    • Set transplants outBrussels sproutMar 19 to Apr 2
    • Set transplants outCabbagefrom Mar 19
    • Set transplants outKalefrom Mar 19
    • Set transplants outKohlrabifrom Mar 19
    • Set transplants outLeekfrom Mar 19
    • Set transplants outLettuceMar 19 to Mar 26
    • Set transplants outOnionfrom Mar 19
  10. Week of Mar 263 weeks before last frost
    • Start seeds indoorsCucumberMar 26 to Apr 2
    • Set transplants outParsleyMar 26 to Apr 2
  11. Week of Apr 22 weeks before last frost
    • Start seeds indoorsMelonApr 2 to Apr 9
    • Start seeds indoorsPumpkinApr 2 to Apr 9
    • Start seeds indoorsSummer squashApr 2 to Apr 9
    • Start seeds indoorsWinter squashApr 2 to Apr 9
    • Start seeds indoorsZucchiniApr 2 to Apr 9
    • Plant seed potatoes outdoorsPotatoApr 2 to Apr 9
    • Set transplants outCauliflowerfrom Apr 2
    • Set transplants outSwiss chardfrom Apr 2
  12. Week of Apr 16Last frost week
    • Sow seed outdoorsBeanfrom Apr 16
    • Sow seed outdoorsParsnipfrom Apr 16
    • Set transplants outCeleryfrom Apr 16
  13. Week of Apr 231 week after last frost
    • Plant slips outdoorsSweet potatoApr 23 to Apr 30
    • Set transplants outCucumberApr 23 to Apr 30
    • Set transplants outTomatoApr 23 to Apr 30
  14. Week of Apr 302 weeks after last frost
    • Set transplants outBasilfrom Apr 30
    • Set transplants outEggplantApr 30 to May 7
    • Set transplants outMelonfrom Apr 30
    • Set transplants outPepperfrom Apr 30
    • Set transplants outPumpkinfrom Apr 30
    • Set transplants outSummer squashfrom Apr 30
    • Set transplants outWinter squashfrom Apr 30
    • Set transplants outZucchinifrom Apr 30

Not in the city centre? Look up your own ZIP code

More in Ohio

Where the numbers come from

Sources and method

Frost dates. U.S. Climate Normals 2020: U.S. Annual/Seasonal Climate Normals (1991-2020), NOAA National Centers for Environmental Information (Palecki, Durre, Applequist, Arguez and Lawrimore, 2021). These are 30-year station statistics for 1991 to 2020. "Frost" here means an air temperature of 32°F or lower at the station. We use 6,539 stations that have at least 10 years of record and a published date; 176 more are stations where a freeze is too rare for NOAA to date, and 180 are stations cold enough to have frost risk all year.

Probability level. The headline dates are NOAA's 50% level: in half of years the last spring freeze comes later than that date, and in half of years the first fall freeze comes earlier. The 10% and 90% levels are shown next to them. For tender plants, the 10% spring date is the safer one to plan from: a freeze follows it in only 1 year in 10.

Which station. Your ZIP code is matched to the nearest of those stations by straight-line distance from the ZIP code's centre point (GeoNames, geonames.org, CC BY 4.0; 40,979 ZIP codes in the 50 states and DC). Nearest is not always most alike: a station on a hill, in a valley or by the water can differ from your garden by a week or more. That is why the station's name, distance and elevation are shown with every result, along with two more stations nearby. NOAA makes the same point: the normals are limited between stations as distance grows horizontally and vertically.

Seed-starting offsets. Growing Vegetables: When to Plant Your Vegetable Garden, a fact sheet from University of New Hampshire Extension. It gives each crop's weeks from seed to transplant and when it is safe to set out or sow relative to the last frost. The method is theirs too: take the planting date and count back the seed-to-transplant weeks. Where the fact sheet gives a range of planting dates, the start-indoors dates count back from the earliest one. The figures used, as the fact sheet states them:

  • Basil: Seed to transplant 6-8 weeks; set out 2 weeks after last frost.
  • Bean: Plant seed in garden after last frost.
  • Broccoli: Seed to transplant 4-6 weeks; set out 2-4 weeks before last frost.
  • Brussels sprout: Seed to transplant 4-6 weeks; set out 2-4 weeks before last frost.
  • Cabbage: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Cauliflower: Seed to transplant 4-6 weeks; set out 2 weeks before last frost.
  • Celery: Seed to transplant 10-12 weeks; set out after last frost.
  • Cucumber: Seed to transplant 3-4 weeks; set out 1-2 weeks after last frost.
  • Eggplant: Seed to transplant 8-10 weeks; set out 2-3 weeks after last frost.
  • Kale: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Kohlrabi: Seed to transplant 4-6 weeks; set out 4 weeks before last frost.
  • Leek: Seed to transplant 8-10 weeks; set out 4 weeks before last frost.
  • Lettuce: Seed to transplant 4-5 weeks; set out 3-4 weeks before last frost.
  • Melon: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Onion: Seed to transplant 8-10 weeks; set out 4 weeks before last frost.
  • Parsley: Seed to transplant 9-10 weeks; set out 2-3 weeks before last frost.
  • Parsnip: Plant seed in garden after last frost.
  • Pepper: Seed to transplant 8-10 weeks; set out 2 weeks after last frost.
  • Potato: Plant seed potatoes in garden 1-2 weeks before last frost.
  • Pumpkin: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Radish: Plant seed in garden 2-4 weeks before last frost.
  • Spinach: Seed to transplant 4-6 weeks; set out 3-6 weeks before last frost.
  • Summer squash: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Sweet potato: Plant slips in garden 1-2 weeks after last frost.
  • Swiss chard: Seed to transplant 4-6 weeks; set out 2 weeks before last frost; or plant seed in garden 4 weeks before last frost.
  • Tomato: Seed to transplant 6-8 weeks; set out 1-2 weeks after last frost.
  • Turnip: Plant seed in garden 2-4 weeks before last frost.
  • Winter squash: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.
  • Zucchini: Seed to transplant 3-4 weeks; set out 2 weeks after last frost.

Not on the calendar. The same fact sheet times these by soil temperature, not by frost date, so they get no date here:

  • Pea: as soon as the soil thaws.
  • Beet: when the soil warms to 45°F.
  • Carrot: when the soil warms to 60°F.
  • Corn: when the soil warms to 60°F.
  • Cucumber, pumpkin, summer squash, winter squash, zucchini: direct-sow when the soil warms to 70°F.

Rutabaga is left out: the fact sheet gives it New Hampshire calendar dates, not a frost offset.

The fact sheet was written for New Hampshire. The offsets are relative to the last frost, so they carry to other places with a spring frost, but where winters are mild many cool-season crops are grown in fall and winter instead. Your state's extension service has the local calendar. Dates are 30-year statistics, not a forecast: check the forecast before setting tender plants out.

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