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Frost dates and planting calendar for Fort Mill, South Carolina

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

USDA hardiness zone
8a[1]
Median last spring frost
Mar 27[2]
Median first fall frost
Nov 5[3]
Growing season, median
225 days[4]

Fort Mill, South Carolina is in USDA hardiness zone 8a[1]. The median last spring frost is March 27, which means a last frost after that date in half of years[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 10, half of years Mar 27, 1 in 10 years after Apr 11Last frostmedian Mar 27First fall frost: 9 in 10 years before Nov 23, half of years Nov 5, 1 in 10 years before Oct 24First frostmedian Nov 5Frost riskHardyHardy vegetables: plant Feb 27 to Mar 13Feb 27 to Mar 13Semi-hardySemi-hardy vegetables: plant Mar 13 to Mar 27Mar 13 to Mar 27TenderTender vegetables: plant around Mar 27around Mar 27Very tenderVery tender vegetables: plant from Apr 10from Apr 10
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.

These frost dates are odds from 1991 to 2020 records, not a forecast[2]. They come from the NOAA weather station at Winthrop Univ, 7 miles from the center of Fort Mill[5]. The last spring frost comes after March 10 in 9 of 10 years and after April 11 in 1 of 10 years[2]. The first fall frost comes before October 24 in 1 of 10 years and before November 23 in 9 of 10 years[3]. The median first frost date is November 5[3].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after March 10 after March 27 after April 11
First fall frost (32°F)[3] before October 24 before November 5 before November 23
  • Hard freeze (28°F): median last spring date March 15, median first fall date November 18[7].
  • Frost-free growing season: at least 205 days in 9 of 10 years, 225 days in half of years and 248 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: Winthrop Univ (USC00389350), 7 miles from the city center, 650 feet, 28 years of 1991 to 2020 records[5].

When to plant vegetables

The planting rules here come from Colorado State University Extension, whose guide was written for Colorado[6]. We took the NOAA median last frost of March 27 as the average last frost and did the arithmetic[6]. Hardy vegetables such as broccoli, lettuce and peas can go in as early as 2 to 4 weeks before it, which is February 27 to March 13[6]. Tender vegetables such as snap beans and sweet corn can be planted from seed around March 27[9]. Very tender vegetables such as tomatoes and peppers typically wait 2 or more weeks after it, so the earliest start is April 10[10].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (March 27) is February 27 to March 13[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (March 27) is March 13, up to the median date itself[11]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, March 27[9]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (March 27), is April 10[10]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Feb 27 May 3 (from transplants)
Cabbage (hardy)[12] Feb 27 May 23 (from transplants)
Kohlrabi (hardy)[12] Feb 27 Apr 18
Lettuce (hardy)[12] Feb 27 Apr 28
Onions (hardy)[12] Feb 27 Jun 17
Peas (hardy)[12] Feb 27 May 3
Radishes (hardy)[12] Feb 27 Mar 29
Spinach (hardy)[12] Feb 27 Apr 8
Turnips (hardy)[12] Feb 27 Apr 18
Beets (semi-hardy)[12] Mar 13 May 12
Carrots (semi-hardy)[12] Mar 13 May 22
Cauliflower (semi-hardy)[12] Mar 13 not listed
Parsnips (semi-hardy)[12] Mar 13 May 22
Potatoes (semi-hardy)[12] Mar 13 Jul 16
Swiss chard (semi-hardy)[12] Mar 13 May 12
Snap beans (tender)[12] Mar 27 May 26
Sweet corn (tender)[12] Mar 27 May 26
Cucumbers (tender)[12] Mar 27 May 21
Summer squash (tender)[12] Mar 27 May 16
Cantaloupe (very tender)[12] Apr 10 Jul 4
Eggplant (very tender)[12] Apr 10 Jun 9 (from transplants)
Peppers (very tender)[12] Apr 10 Jun 19 (from transplants)
Tomatoes (very tender)[12] Apr 10 Jun 14 (from transplants)
Winter squash (very tender)[12] Apr 10 Jul 19
Watermelon (very tender)[12] Apr 10 Jul 4
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 8a means an average coldest night of the winter between 10°F and 15°F over 1991 to 2020[1]. The zone is not about summer heat or frost dates[14]. All of Fort Mill's land area lies in ZIP code areas rated zone 8a[15].

Zone 8a: average annual extreme minimum temperature 10°F to 15°F (1991 to 2020)[1]. Modeled value at the city center: 13.3°F[1].

Share of the city's land area by ZIP code zone: zone 8a 100%[15].

All towns in zone 8a and what zone 8a means

Zone by ZIP code
ZIP code Zone Coldest night range
29715[15] 8a 10 to 15°F
29708[15] 8a 10 to 15°F

Questions people ask

What growing zone is Fort Mill?
The 2023 USDA map puts the center of Fort Mill in zone 8a[1].
When is the last frost in Fort Mill?
The median last spring frost is March 27, so in half of years the last frost comes after that date[2]. In 1 of 10 years it comes after April 11[2].
When is the first frost in Fort Mill?
The median first fall frost is November 5[3]. In 1 of 10 years it comes before October 24[3].
When to plant tomatoes in Fort Mill?
CSU Extension groups tomatoes as very tender and typically 2 or more weeks after the average last frost, which gives an earliest start of April 10[10].
How long is the growing season in Fort Mill?
The season between the last spring and first fall frost is at least 225 days in half of years[4]. It is at least 205 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Fort Mill, South Carolina in zone 8a. Zone 8a means an average annual extreme minimum temperature of 10°F to 15°F over 1991 to 2020. The map's modeled value at the city center is 13.3°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 March 10, in half of years after March 27, and in 1 of 10 years after April 11 (NOAA 1991 to 2020 normals). The median last frost date is March 27. 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 24, in half of years before November 5, and in 9 of 10 years before November 23 (NOAA 1991 to 2020 normals). The median first frost date is November 5. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 205 days in 9 of 10 years, at least 225 days in half of years, and at least 248 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Winthrop Univ weather station (USC00389350), 7 miles from the center of Fort Mill at 650 feet, using 28 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 March 15 and the median first fall date is November 18. 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 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
  10. 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
  11. 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
  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. Fort Mill, South Carolina overlaps 2 ZIP code areas. By land area, 100% lies in ZIP code areas rated zone 8a. 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.