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Frost dates and planting calendar for Chattanooga, Tennessee

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 24[2]
Median first fall frost
Nov 9[3]
Growing season, median
230 days[4]

Chattanooga, Tennessee is in USDA hardiness zone 8a[1]. The median last spring frost at the Chattanooga airport station is March 24[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 6, half of years Mar 24, 1 in 10 years after Apr 8Last frostmedian Mar 24First fall frost: 9 in 10 years before Nov 26, half of years Nov 9, 1 in 10 years before Oct 27First frostmedian Nov 9Frost riskHardyHardy vegetables: plant Feb 24 to Mar 10Feb 24 to Mar 10Semi-hardySemi-hardy vegetables: plant Mar 10 to Mar 24Mar 10 to Mar 24TenderTender vegetables: plant around Mar 24around Mar 24Very tenderVery tender vegetables: plant from Apr 7from Apr 7
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.

NOAA frost dates for Chattanooga come from the Lovell Airport weather station, using 27 years of records from 1991 to 2020[5]. In half of years the last spring frost comes after March 24, and in 1 of 10 years it comes after April 8[2]. In half of years the first fall frost comes before November 9, and in 1 of 10 years it comes before October 27[3]. These are odds from past records, not a forecast, so any year can be earlier or later[2].

Frost Likely (9 in 10 years) Even odds (5 in 10) Unlikely (1 in 10)
Last spring frost (32°F)[2] after March 6 after March 24 after April 8
First fall frost (32°F)[3] before October 27 before November 9 before November 26
  • Hard freeze (28°F): median last spring date March 11, median first fall date November 22[7].
  • Frost-free growing season: at least 210 days in 9 of 10 years, 230 days in half of years and 254 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: Chattanooga Lovell Airport (USW00013882), 3.6 miles from the city center, 671 feet, 27 years of 1991 to 2020 records[5].

When to plant vegetables

Colorado State University Extension's planting guide was written for Colorado, so these dates are simple arithmetic and not local advice[6]. Hardy vegetables such as broccoli, lettuce, peas and spinach can go in as early as 2 to 4 weeks before the median last frost, which works out to February 24 to March 10[6]. Semi-hardy vegetables such as beets, carrots and potatoes can go in as early as 2 weeks before the median last frost, which is March 10[9]. Tender vegetables such as snap beans and sweet corn are planted from seed around the median last frost date, March 24[10]. Very tender vegetables such as tomatoes and peppers typically start 2 or more weeks after it, and the earliest start is April 7[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (March 24) is February 24 to March 10[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (March 24) is March 10, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, March 24[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (March 24), is April 7[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Feb 24 Apr 30 (from transplants)
Cabbage (hardy)[12] Feb 24 May 20 (from transplants)
Kohlrabi (hardy)[12] Feb 24 Apr 15
Lettuce (hardy)[12] Feb 24 Apr 25
Onions (hardy)[12] Feb 24 Jun 14
Peas (hardy)[12] Feb 24 Apr 30
Radishes (hardy)[12] Feb 24 Mar 26
Spinach (hardy)[12] Feb 24 Apr 5
Turnips (hardy)[12] Feb 24 Apr 15
Beets (semi-hardy)[12] Mar 10 May 9
Carrots (semi-hardy)[12] Mar 10 May 19
Cauliflower (semi-hardy)[12] Mar 10 not listed
Parsnips (semi-hardy)[12] Mar 10 May 19
Potatoes (semi-hardy)[12] Mar 10 Jul 13
Swiss chard (semi-hardy)[12] Mar 10 May 9
Snap beans (tender)[12] Mar 24 May 23
Sweet corn (tender)[12] Mar 24 May 23
Cucumbers (tender)[12] Mar 24 May 18
Summer squash (tender)[12] Mar 24 May 13
Cantaloupe (very tender)[12] Apr 7 Jul 1
Eggplant (very tender)[12] Apr 7 Jun 6 (from transplants)
Peppers (very tender)[12] Apr 7 Jun 16 (from transplants)
Tomatoes (very tender)[12] Apr 7 Jun 11 (from transplants)
Winter squash (very tender)[12] Apr 7 Jul 16
Watermelon (very tender)[12] Apr 7 Jul 1
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 winter night of 10°F to 15°F over 1991 to 2020[1]. The zone is based on that coldest night, not on summer heat or frost dates[14]. Chattanooga overlaps 20 ZIP code areas[15]. By land area, 80% lies in zone 8a and 20% lies in zone 7b[15].

Zone 8a: average annual extreme minimum temperature 10°F to 15°F (1991 to 2020)[1]. Modeled value at the city center: 12.4°F[1].

Share of the city's land area by ZIP code zone: zone 8a 80%, zone 7b 20%[15].

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

Zone by ZIP code
ZIP code Zone Coldest night range
37421[15] 8a 10 to 15°F
37343[15] 8a 10 to 15°F
37419[15] 7b 5 to 10°F
37416[15] 8a 10 to 15°F
37406[15] 8a 10 to 15°F
37405[15] 7b 5 to 10°F
37415[15] 8a 10 to 15°F
37411[15] 8a 10 to 15°F
37404[15] 8a 10 to 15°F
37409[15] 8a 10 to 15°F
37407[15] 8a 10 to 15°F
37410[15] 8a 10 to 15°F
37363[15] 8a 10 to 15°F
37408[15] 8a 10 to 15°F
37403[15] 8a 10 to 15°F
37402[15] 8a 10 to 15°F
37412[15] 8a 10 to 15°F
37341[15] 8a 10 to 15°F
37351[15] 8a 10 to 15°F
37377[15] 7b 5 to 10°F

Questions people ask

What growing zone is Chattanooga?
The 2023 USDA map puts the center of Chattanooga in zone 8a[1]. By land area, 80% of the city is in zone 8a and 20% is in zone 7b[15].
When is the last frost in Chattanooga?
The median last spring frost is March 24, so in half of years the last frost comes after that date[2]. In 1 of 10 years it comes after April 8[2].
When to plant tomatoes in Chattanooga?
CSU Extension says tomatoes typically go in 2 or more weeks after the average last frost[11]. Using the median last frost, the earliest start is April 7[11].
When is the first frost in Chattanooga?
The median first fall frost is November 9, so in half of years it comes before that date[3]. In 1 of 10 years it comes before October 27[3].
How long is the growing season in Chattanooga?
The growing season is at least 230 days in half of years[4]. It is at least 210 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Chattanooga, Tennessee 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 12.4°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 6, in half of years after March 24, and in 1 of 10 years after April 8 (NOAA 1991 to 2020 normals). The median last frost date is March 24. 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 27, in half of years before November 9, and in 9 of 10 years before November 26 (NOAA 1991 to 2020 normals). The median first frost date is November 9. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 210 days in 9 of 10 years, at least 230 days in half of years, and at least 254 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Chattanooga Lovell Airport weather station (USW00013882), 3.6 miles from the center of Chattanooga at 671 feet, using 27 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 11 and the median first fall date is November 22. 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. Chattanooga, Tennessee overlaps 20 ZIP code areas. By land area, 80% lies in ZIP code areas rated zone 8a, 20% lies in ZIP code areas rated zone 7b. 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.