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Frost dates and planting calendar for Salt Lake City, Utah

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

USDA hardiness zone
7b[1]
Median last spring frost
Apr 8[2]
Median first fall frost
Oct 31[3]
Growing season, median
204 days[4]

The USDA hardiness zone map puts the center of Salt Lake City in zone 7b[1]. NOAA records give a median last spring frost of April 8, so in half of years the last frost comes after that date[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 17, half of years Apr 8, 1 in 10 years after Apr 30Last frostmedian Apr 8First fall frost: 9 in 10 years before Nov 13, half of years Oct 31, 1 in 10 years before Oct 17First frostmedian Oct 31Frost riskHardyHardy vegetables: plant Mar 11 to Mar 25Mar 11 to Mar 25Semi-hardySemi-hardy vegetables: plant Mar 25 to Apr 8Mar 25 to Apr 8TenderTender vegetables: plant around Apr 8around Apr 8Very tenderVery tender vegetables: plant from Apr 22from Apr 22
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, not promises, built from NOAA climate normals for the Salt Lake City International Airport station, 1991 to 2020[5]. In half of years the last spring frost comes after April 8, and in 1 of 10 years it comes after April 30[2]. In the fall, the first frost comes before October 17 in 1 of 10 years and before October 31 in half of years[3]. Any single 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 March 17 after April 8 after April 30
First fall frost (32°F)[3] before October 17 before October 31 before November 13
  • Hard freeze (28°F): median last spring date March 15, median first fall date November 10[7].
  • Frost-free growing season: at least 177 days in 9 of 10 years, 204 days in half of years and 229 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: Salt Lake City International Airport (USW00024127), 2 miles from the city center, 4,225 feet, 29 years of 1991 to 2020 records[5].

When to plant vegetables

The planting dates here use Colorado State University Extension's vegetable guide, which was written for Colorado[6]. Hardy crops such as peas, lettuce and spinach can go in as early as March 11 to March 25, which is 2 to 4 weeks before the median last frost[6]. Semi-hardy crops such as beets, carrots and potatoes can start as early as March 25, up to April 8[9]. Tender crops such as snap beans and sweet corn go in from seed around the median last frost date, April 8[10]. Very tender crops such as tomatoes, peppers and eggplant typically wait 2 or more weeks after the median last frost, so April 22 is the earliest start, not the planting day[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 8) is March 11 to March 25[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 8) is March 25, up to the median date itself[9]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 8[10]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 8), is April 22[11]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[12] Mar 11 May 15 (from transplants)
Cabbage (hardy)[12] Mar 11 Jun 4 (from transplants)
Kohlrabi (hardy)[12] Mar 11 Apr 30
Lettuce (hardy)[12] Mar 11 May 10
Onions (hardy)[12] Mar 11 Jun 29
Peas (hardy)[12] Mar 11 May 15
Radishes (hardy)[12] Mar 11 Apr 10
Spinach (hardy)[12] Mar 11 Apr 20
Turnips (hardy)[12] Mar 11 Apr 30
Beets (semi-hardy)[12] Mar 25 May 24
Carrots (semi-hardy)[12] Mar 25 Jun 3
Cauliflower (semi-hardy)[12] Mar 25 not listed
Parsnips (semi-hardy)[12] Mar 25 Jun 3
Potatoes (semi-hardy)[12] Mar 25 Jul 28
Swiss chard (semi-hardy)[12] Mar 25 May 24
Snap beans (tender)[12] Apr 8 Jun 7
Sweet corn (tender)[12] Apr 8 Jun 7
Cucumbers (tender)[12] Apr 8 Jun 2
Summer squash (tender)[12] Apr 8 May 28
Cantaloupe (very tender)[12] Apr 22 Jul 16
Eggplant (very tender)[12] Apr 22 Jun 21 (from transplants)
Peppers (very tender)[12] Apr 22 Jul 1 (from transplants)
Tomatoes (very tender)[12] Apr 22 Jun 26 (from transplants)
Winter squash (very tender)[12] Apr 22 Jul 31
Watermelon (very tender)[12] Apr 22 Jul 16
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

The zone is based on the average coldest winter night, not on frost dates or summer heat[14]. Zone 7b means an average annual extreme minimum of 5°F to 10°F over 1991 to 2020[1]. USDA says the map helps gardeners judge which perennial plants are most likely to thrive[14]. Salt Lake City spans more than one zone: by land area, 69% lies in ZIP code areas rated 7b, 30% in 6b and 1% in 7a[15].

Zone 7b: average annual extreme minimum temperature 5°F to 10°F (1991 to 2020)[1]. Modeled value at the city center: 6.2°F[1].

Share of the city's land area by ZIP code zone: zone 7b 69%, zone 6b 30%, zone 7a 1%[15].

All towns in zone 7b and what zone 7b means

Zone by ZIP code
ZIP code Zone Coldest night range
84116[15] 7b 5 to 10°F
84104[15] 7b 5 to 10°F
84103[15] 6b -5 to 0°F
84108[15] 6b -5 to 0°F
84106[15] 7b 5 to 10°F
84105[15] 7b 5 to 10°F
84044[15] 7b 5 to 10°F
84102[15] 7b 5 to 10°F
84115[15] 7b 5 to 10°F
84101[15] 7b 5 to 10°F
84109[15] 6b -5 to 0°F
84128[15] 7b 5 to 10°F
84111[15] 7b 5 to 10°F
84112[15] 7a 0 to 5°F
84119[15] 7b 5 to 10°F
84113[15] 7a 0 to 5°F
84114[15] 7b 5 to 10°F
84180[15] 7b 5 to 10°F

Questions people ask

What growing zone is Salt Lake City?
The 2023 USDA map puts the center of Salt Lake City in zone 7b[1]. By land area, 30% of the city lies in ZIP code areas rated zone 6b[15].
When is the last frost in Salt Lake City?
The median last spring frost is April 8, based on NOAA records[2]. In 1 of 10 years the last frost comes after April 30[2].
When to plant tomatoes in Salt Lake City?
CSU Extension says tomatoes typically go in 2 or more weeks after the average last frost[11]. For Salt Lake City that makes April 22 the earliest start[11].
When is the first frost in Salt Lake City?
The median first fall frost is October 31[3]. In 1 of 10 years it comes before October 17[3].
How long is the growing season in Salt Lake City?
In half of years the growing season lasts at least 204 days[4]. In 9 of 10 years it lasts at least 177 days[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Salt Lake City, Utah in zone 7b. Zone 7b means an average annual extreme minimum temperature of 5°F to 10°F over 1991 to 2020. The map's modeled value at the city center is 6.2°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 March 17, in half of years after April 8, and in 1 of 10 years after April 30 (NOAA 1991 to 2020 normals). The median last frost date is April 8. 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 17, in half of years before October 31, and in 9 of 10 years before November 13 (NOAA 1991 to 2020 normals). The median first frost date is October 31. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 177 days in 9 of 10 years, at least 204 days in half of years, and at least 229 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Salt Lake City International Airport weather station (USW00024127), 2 miles from the center of Salt Lake City at 4,225 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 March 15 and the median first fall date is November 10. 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. Salt Lake City, Utah overlaps 18 ZIP code areas. By land area, 69% lies in ZIP code areas rated zone 7b, 30% lies in ZIP code areas rated zone 6b, 1% lies in ZIP code areas rated zone 7a. 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.