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USDA Hardiness Zone 6b

Frost Dates for 45236 — Cincinnati, Ohio

NOAA 1991–2020 normals from Milford, OH (520 ft), 6 miles east.

Updated

In Cincinnati, the last spring frost (32°F) is around April 23 in half of years and has passed by May 8 in nine years out of ten. The first fall frost comes around October 18, as early as October 6 one year in ten, leaving a typical freeze-free season of 177 days (NOAA, Milford, OH).

Last spring frost
April 23

50% probability

First fall frost
October 18

50% probability

Growing season
177 days

freeze-free, 50%

Hardiness zone
6b

-5 to 0°F (-20.6 to -17.8°C) coldest night

First snow
December 11

median, 1991–2020

Last snow
March 13

median, 1991–2020

Winters with snow
100%

20 of 20 observed

Snow per year
14.4"

NOAA normal

Frost risk by date in Cincinnati

Half of springs at Milford, OH see their last 32°F night by April 23; only one in ten is past it by April 9, and one in ten still has one after May 8. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 3 20%, and after May 8 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 77% of the 148 Ohio stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 6 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 9 days later, around October 27; in spring the one-in-ten date for 28°F is April 28, 10 days before the 32°F one. The freeze-free season lasts 177 days in a typical year, shorter than at 61% of the 148 Ohio stations; it reaches 193 days one year in ten and falls short of 158 one year in ten. On average 116 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 9 days longer, to about May 2, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 4 and March 11.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 19Apr 23Apr 27Apr 30May 2May 5May 8May 11May 16
32°FApr 9Apr 14Apr 17Apr 20Apr 23Apr 25Apr 30May 3May 8
28°FMar 31Apr 3Apr 5Apr 8Apr 11Apr 14Apr 17Apr 21Apr 28
24°FMar 17Mar 22Mar 26Mar 30Apr 1Apr 3Apr 5Apr 8Apr 14
20°FMar 4Mar 10Mar 14Mar 18Mar 21Mar 24Mar 27Mar 31Apr 3
16°FFeb 19Feb 27Mar 3Mar 8Mar 11Mar 15Mar 18Mar 21Mar 26
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 29Oct 3Oct 5Oct 7Oct 9Oct 11Oct 13Oct 15Oct 18
32°FOct 6Oct 10Oct 13Oct 16Oct 18Oct 20Oct 22Oct 24Oct 28
28°FOct 16Oct 20Oct 23Oct 25Oct 27Oct 30Nov 1Nov 4Nov 9
24°FOct 24Oct 30Nov 1Nov 3Nov 7Nov 10Nov 13Nov 18Nov 26
20°FNov 3Nov 9Nov 13Nov 17Nov 21Nov 26Dec 1Dec 4Dec 11
16°FNov 14Nov 21Nov 27Dec 1Dec 4Dec 8Dec 14Dec 20Dec 27

Freeze probabilities 1991–2020 at Milford, OH, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 45236 →Compare Cincinnati with another place →

Weather by month in Cincinnati

July is the warmest month at Milford, OH, averaging 87°F by day and 64°F at night; January is the coldest at 39°F and 22°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 26% of years.

Warmth for growing adds up to 3,636 growing degree days a year (base 50°F), more than at 86% of the 148 Ohio stations. 36% of them (1,322) have built up by the end of June, and July adds the most, 787.

Monthly normals 1991–2020 at Milford, OH
MonthHigh °FLow °F32°F nightNights ≤ 32°FGDD 50°F
Jan3922100%267
Feb4324100%235
Mar5431100%1843
Apr6641100%7175
May765126%<1425
Jun84610%0667
Jul87640%0787
Aug86630%0761
Sep80541%0509
Oct684296%4194
Nov5533100%1554
Dec4326100%248

Monthly normals 1991–2020 at Milford, OH (520 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Cincinnati Lunken Airport, OH, 7 miles south of Cincinnati, has a last frost 7 days earlier (April 16), a first frost 7 days later (October 25), a season 13 days longer.

Frost dates for 45215 (Cincinnati) →

When it snows in Cincinnati, Ohio

The first measurable snow (0.1 inch or more) in Cincinnati usually arrives around December 11, and the last of the season around March 13. Those are the middle dates across the winters of 1991–2020 at Kings Mills, OH, 12.5 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 41 days after the last snow.

Planting calendar for 45236

What to do and when, from the 50% frost dates for Cincinnati, Ohio
WhenWhat to do
February 12 – February 26Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
February 26 – March 12Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
March 26 – April 9Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 23 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 26Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by October 4Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 18 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 45236 is 6 miles from Milford, OH, which stands at 520 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 16 other ZIP codes share the station; its figures are presented in full for 45140 (Loveland). The 2023 USDA Plant Hardiness Zone Map lists ZIP 45236 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Ohio →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

ZIP codes measured at the same station

Other zone 6b places in Ohio