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Frost dates and planting calendar for Cincinnati, Ohio

Updated October 30, 2026. Based on USDA, NOAA and Colorado State University Extension data. Published by Humblebee.

USDA hardiness zone
6b[1]
Median last spring frost
Apr 16[2]
Median first fall frost
Oct 25[3]
Growing season, median
190 days[4]

Cincinnati, Ohio sits in USDA hardiness zone 6b[1]. In half of years the last spring frost comes after April 16, the median date at the nearby NOAA station[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Apr 2, half of years Apr 16, 1 in 10 years after May 3Last frostmedian Apr 16First fall frost: 9 in 10 years before Nov 5, half of years Oct 25, 1 in 10 years before Oct 12First frostmedian Oct 25Frost riskHardyHardy vegetables: plant Mar 19 to Apr 2Mar 19 to Apr 2Semi-hardySemi-hardy vegetables: plant Apr 2 to Apr 16Apr 2 to Apr 16TenderTender vegetables: plant around Apr 16around Apr 16Very tenderVery tender vegetables: plant from Apr 30from Apr 30
Shaded: the span between the dates frost passes in 9 of 10 years and 1 of 10 years[2][3]. Green: planting windows from the CSU rules applied to the median last frost (GardenFacts calculation)[6]. Exact dates are in the tables below.

Frost dates here are odds, not promises. They come from NOAA climate normals for the Cincinnati Lunken Airport weather station, using records from 1991 to 2020[5]. In spring, the last frost comes after April 2 in 9 of 10 years, after April 16 in half of years, and after May 3 in 1 of 10 years[2]. In fall, the first frost comes before October 12 in 1 of 10 years and before October 25 in half of years[3]. Any year can be earlier or later than these numbers.

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after April 2 after April 16 after May 3
First fall frost (32°F)[3] before October 12 before October 25 before November 5
  • Hard freeze (28°F): median last spring date April 2, median first fall date November 4[7].
  • Frost-free growing season: at least 168 days in 9 of 10 years, 190 days in half of years and 210 days in 1 of 10 years[4].
  • The low reached 32°F or colder in 100% of years and 28°F or colder in 100% of years[8].
  • Weather station: Cincinnati Lunken Airport (USW00093812), 5.3 miles from the city center, 490 feet, 29 years of 1991 to 2020 records[5].

When to plant vegetables

The planting dates on this page use Colorado State University Extension's vegetable guide, which was written for Colorado[6]. GardenFacts takes the NOAA median last frost, April 16, as the average last frost and does simple arithmetic from CSU's rules[6]. Hardy crops like peas, lettuce and spinach can go in as early as March 19 to April 2[6]. Semi-hardy crops like beets and carrots can go in as early as April 2, up to April 16[9]. Tender crops like snap beans and sweet corn go in from seed around April 16[10], and very tender crops like tomatoes and peppers typically wait 2 or more weeks after the average last frost, and two weeks after the median last frost (April 16) gives April 30 as the earliest start[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 16) is March 19 to April 2[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 16) is April 2, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 16[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 16), is April 30[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Mar 19 May 23 (from transplants)
Cabbage (hardy)[12] Mar 19 Jun 12 (from transplants)
Kohlrabi (hardy)[12] Mar 19 May 8
Lettuce (hardy)[12] Mar 19 May 18
Onions (hardy)[12] Mar 19 Jul 7
Peas (hardy)[12] Mar 19 May 23
Radishes (hardy)[12] Mar 19 Apr 18
Spinach (hardy)[12] Mar 19 Apr 28
Turnips (hardy)[12] Mar 19 May 8
Beets (semi-hardy)[12] Apr 2 Jun 1
Carrots (semi-hardy)[12] Apr 2 Jun 11
Cauliflower (semi-hardy)[12] Apr 2 not listed
Parsnips (semi-hardy)[12] Apr 2 Jun 11
Potatoes (semi-hardy)[12] Apr 2 Aug 5
Swiss chard (semi-hardy)[12] Apr 2 Jun 1
Snap beans (tender)[12] Apr 16 Jun 15
Sweet corn (tender)[12] Apr 16 Jun 15
Cucumbers (tender)[12] Apr 16 Jun 10
Summer squash (tender)[12] Apr 16 Jun 5
Cantaloupe (very tender)[12] Apr 30 Jul 24
Eggplant (very tender)[12] Apr 30 Jun 29 (from transplants)
Peppers (very tender)[12] Apr 30 Jul 9 (from transplants)
Tomatoes (very tender)[12] Apr 30 Jul 4 (from transplants)
Winter squash (very tender)[12] Apr 30 Aug 8
Watermelon (very tender)[12] Apr 30 Jul 24
Spacing, depth and soil temperature (CSU Extension)
Vegetable Min. soil temp Depth Spacing Days to harvest
Broccoli[13] 40°F 1/2 in 18 in 65
Cabbage[13] 40°F 1/2 in 18 in 85
Kohlrabi[13] 40°F 1/2 in 7-9 in 50
Lettuce[13] 35°F 1/4 in 7-9 in 60
Onions[13] 35°F 1/4 in (seed), 1-2 in (sets) 4-6 in 110
Peas[13] 40°F 1 in 4-6 in 65
Radishes[13] 40°F 1/2 in 2-3 in 30
Spinach[13] 40°F 1/2 in 4-6 in 40
Turnips[13] 40°F 1/2 in 4-6 in 50
Beets[13] 40°F 3/4-1 in 4-6 in 60
Carrots[13] 40°F 1/4 in 2-3 in 70
Cauliflower[13] 40°F 1/2 in 18 in –
Parsnips[13] 35°F 1/2 in 5-6 in 70
Potatoes[13] 45°F – – 125
Swiss chard[13] 40°F 1 in 7-9 in 60
Snap beans[13] 55°F 1-1 1/2 in 6 in 60
Sweet corn[13] 50°F 1-1 1/2 in 12 x 30 in or 9 x 36 in 60-90
Cucumbers[13] 60°F 1 in 6 in trellised, 24-36 in untrellised 55
Summer squash[13] 60°F 1-1 1/2 in 36-48 in 50
Cantaloupe[13] 60°F 1-1 1/2 in 36-48 in 85
Eggplant[13] 60°F 1/4 in 18-24 in 60
Peppers[13] 60°F 1/4 in 15-18 in 70
Tomatoes[13] 50°F 1/4 in 24 in trellised 65
Winter squash[13] 60°F 1-1 1/2 in 36-48 in 100
Watermelon[13] 60°F 1-1 1/2 in 36-48 in 85

Hardiness zone

Zone 6b means the coldest winter night averages -5°F to 0°F, based on 1991 to 2020[1]. The zone is about winter cold, not summer heat or frost dates, and USDA uses it to judge which perennial plants are most likely to thrive[14]. By land area, 100% of Cincinnati lies in ZIP code areas rated zone 6b[15].

Zone 6b: average annual extreme minimum temperature -5°F to 0°F (1991 to 2020)[1]. Modeled value at the city center: -1.2°F[1].

Share of the city's land area by ZIP code zone: zone 6b 100%[15].

All towns in zone 6b and what zone 6b means

Zone by ZIP code
ZIP code Zone Coldest night range
45230[15] 6b -5 to 0°F
45226[15] 6b -5 to 0°F
45211[15] 6b -5 to 0°F
45223[15] 6b -5 to 0°F
45208[15] 6b -5 to 0°F
45232[15] 6b -5 to 0°F
45224[15] 6b -5 to 0°F
45238[15] 6b -5 to 0°F
45237[15] 6b -5 to 0°F
45225[15] 6b -5 to 0°F
45220[15] 6b -5 to 0°F
45204[15] 6b -5 to 0°F
45205[15] 6b -5 to 0°F
45229[15] 6b -5 to 0°F
45214[15] 6b -5 to 0°F
45202[15] 6b -5 to 0°F
45227[15] 6b -5 to 0°F
45213[15] 6b -5 to 0°F
45233[15] 6b -5 to 0°F
45209[15] 6b -5 to 0°F
45206[15] 6b -5 to 0°F
45216[15] 6b -5 to 0°F
45219[15] 6b -5 to 0°F
45203[15] 6b -5 to 0°F
45207[15] 6b -5 to 0°F
45239[15] 6b -5 to 0°F
45212[15] 6b -5 to 0°F
45217[15] 6b -5 to 0°F
45215[15] 6b -5 to 0°F
45267[15] 6b -5 to 0°F

Questions people ask

What growing zone is Cincinnati, Ohio?
The 2023 USDA Plant Hardiness Zone Map puts the center of Cincinnati in zone 6b[1]. By land area, the whole city lies in ZIP code areas rated zone 6b[15].
When is the last frost in Cincinnati?
The median last spring frost is April 16 at the Cincinnati Lunken Airport station[2]. In 1 of 10 years the last frost comes after May 3[2].
When to plant tomatoes in Cincinnati?
CSU Extension groups tomatoes as very tender, typically planted 2 or more weeks after the average last frost[11]. For Cincinnati that makes April 30 the earliest start[11].
When is the first frost in Cincinnati?
The median first fall frost is October 25[3]. In 1 of 10 years the first frost comes before October 12[3].
How long is the growing season in Cincinnati?
In half of years there are at least 190 days between the last spring frost and the first fall frost[4]. In 9 of 10 years there are at least 168 days[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Cincinnati, Ohio in zone 6b. Zone 6b means an average annual extreme minimum temperature of -5°F to 0°F over 1991 to 2020. The map's modeled value at the city center is minus 1.2°F. USDA zone map 2023 (PRISM, OSU)
  2. Last spring frost (32°F) at this station: in 9 of 10 years the last frost comes after April 2, in half of years after April 16, and in 1 of 10 years after May 3 (NOAA 1991 to 2020 normals). The median last frost date is April 16. NOAA Climate Normals 1991-2020
  3. First fall frost (32°F) at this station: in 1 of 10 years the first frost comes before October 12, in half of years before October 25, and in 9 of 10 years before November 5 (NOAA 1991 to 2020 normals). The median first frost date is October 25. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 168 days in 9 of 10 years, at least 190 days in half of years, and at least 210 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Cincinnati Lunken Airport weather station (USW00093812), 5.3 miles from the center of Cincinnati at 490 feet, using 29 years of records from 1991 to 2020. NOAA Climate Normals 1991-2020
  6. Colorado State University Extension's vegetable planting guide (written for Colorado) groups broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips as hardy vegetables, with this rule: as early as 2-4 weeks before the average last... CSU Extension GardenNotes #720
  7. Hard freeze (28°F) at this station: the median last spring date is April 2 and the median first fall date is November 4. NOAA Climate Normals 1991-2020
  8. At this station the low reached 32°F or colder in 100% of years from 1991 to 2020, and 28°F or colder in 100% of years. NOAA Climate Normals 1991-2020
  9. Colorado State University Extension's vegetable planting guide (written for Colorado) groups beets, carrots, cauliflower, parsnips, potatoes, Swiss chard as semi-hardy vegetables, with this rule: as early as 0-2 weeks before the average last spring frost.... CSU Extension GardenNotes #720
  10. Colorado State University Extension's vegetable planting guide (written for Colorado) groups snap beans, sweet corn, cucumbers, summer squash as tender vegetables, with this rule: from seed around the average last spring frost; cucumber and summer squash... CSU Extension GardenNotes #720
  11. Colorado State University Extension's vegetable planting guide (written for Colorado) groups cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon as very tender vegetables, with this rule: typically 2 or more weeks after the average last... CSU Extension GardenNotes #720
  12. GardenFacts calculation: earliest planting date plus CSU days to harvest (table on this page), from the station's median last frost. NOAA Climate Normals 1991-2020
  13. CSU Extension vegetable table: soil temperature, depth, spacing, days to harvest (table on this page). CSU Extension GardenNotes #720
  14. USDA hardiness zones are based on the average annual extreme minimum winter temperature (the coldest night of each winter, averaged over 1991 to 2020 for the 2023 map), not on summer heat or frost dates. Each zone spans 10°F and each half zone (a or b)... USDA Plant Hardiness Zone Map
  15. Cincinnati, Ohio overlaps 32 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 6b. USDA zone map 2023 (PRISM, OSU)

Frost dates are probabilities from 1991 to 2020 weather records at one NOAA station, not a forecast. Any year can be earlier or later. The hardiness zone describes the average coldest winter night, not frost dates or summer heat. Spots inside the city can differ (ZIP table). Planting rules come from Colorado State University Extension's guide, written for Colorado. A local extension office may give dates tuned to the area. Planting and harvest dates marked GardenFacts calculation are simple arithmetic from the facts above, not advice from the source.

Hardiness zone data: USDA Plant Hardiness Zone Map (2023), USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu, accessed October 30, 2026. This is not the official USDA map. Frost data: NOAA NCEI U.S. Climate Normals 1991-2020. Planting rules: Colorado State University Extension.