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Frost dates and planting calendar for Lancaster, California

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

USDA hardiness zone
8b[1]
Median last spring frost
Apr 3[2]
Median first fall frost
Nov 1[3]
Growing season, median
211 days[4]

The USDA 2023 map puts the center of Lancaster, California in zone 8b[1]. The median last spring frost is April 3, which means a last frost after that date in half of years[2].

Frost dates

JanFebMarAprMayJunJulAugSepOctNovDecLast spring frost: 9 in 10 years after Mar 8, half of years Apr 3, 1 in 10 years after Apr 23Last frostmedian Apr 3First fall frost: 9 in 10 years before Nov 14, half of years Nov 1, 1 in 10 years before Oct 17First frostmedian Nov 1Frost riskHardyHardy vegetables: plant Mar 6 to Mar 20Mar 6 to Mar 20Semi-hardySemi-hardy vegetables: plant Mar 20 to Apr 3Mar 20 to Apr 3TenderTender vegetables: plant around Apr 3around Apr 3Very tenderVery tender vegetables: plant from Apr 17from Apr 17
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 dates come from NOAA climate normals for the Lancaster Wm J Fox Field weather station, using records from 1991 to 2020[5]. In 9 of 10 years the last spring frost comes after March 8, and in 1 of 10 years it comes after April 23[2]. In half of years the first fall frost comes before November 1[3]. In 1 of 10 years it comes before October 17, and in 9 of 10 years before November 14[3]. These are odds from past years, 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 8 after April 3 after April 23
First fall frost (32°F)[3] before October 17 before November 1 before November 14
  • Hard freeze (28°F): median last spring date March 8, median first fall date November 10[7].
  • Frost-free growing season: at least 185 days in 9 of 10 years, 211 days in half of years and 240 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: Lancaster Wm J Fox Field (USW00003159), 3.9 miles from the city center, 2,338 feet, 27 years of 1991 to 2020 records[5].

When to plant vegetables

Colorado State University Extension wrote its vegetable planting guide for Colorado, so we use its rules as a starting point only[6]. We take the median last frost of April 3 as the average last frost[6]. Hardy vegetables such as broccoli, lettuce and peas can go in as early as 2 to 4 weeks before that date, which is March 6 to March 20[6]. Tender vegetables such as snap beans and sweet corn can be planted from seed around April 3[9]. Very tender vegetables such as tomatoes and peppers typically wait 2 or more weeks after the last frost, so the earliest start is April 17[10]. Tender and very tender vegetables do not tolerate frost, and the median first fall frost is November 1[11].

  • Hardy (broccoli, cabbage, kohlrabi, lettuce, onions, peas, radishes, spinach, turnips): as early as 2 to 4 weeks before the median last frost (April 3) is March 6 to March 20[6]
  • Semi-hardy (beets, carrots, cauliflower, parsnips, potatoes, Swiss chard): as early as 2 weeks before the median last frost (April 3) is March 20, up to the median date itself[12]
  • Tender (snap beans, sweet corn, cucumbers, summer squash): from seed around the median last frost date, April 3[9]
  • Very tender (cantaloupe, eggplant, peppers, tomatoes, winter squash, watermelon): the earliest start, two weeks after the median last frost (April 3), is April 17[10]
Vegetable (CSU group) Plant from First harvest around
Broccoli (hardy)[13] Mar 6 May 10 (from transplants)
Cabbage (hardy)[13] Mar 6 May 30 (from transplants)
Kohlrabi (hardy)[13] Mar 6 Apr 25
Lettuce (hardy)[13] Mar 6 May 5
Onions (hardy)[13] Mar 6 Jun 24
Peas (hardy)[13] Mar 6 May 10
Radishes (hardy)[13] Mar 6 Apr 5
Spinach (hardy)[13] Mar 6 Apr 15
Turnips (hardy)[13] Mar 6 Apr 25
Beets (semi-hardy)[13] Mar 20 May 19
Carrots (semi-hardy)[13] Mar 20 May 29
Cauliflower (semi-hardy)[13] Mar 20 not listed
Parsnips (semi-hardy)[13] Mar 20 May 29
Potatoes (semi-hardy)[13] Mar 20 Jul 23
Swiss chard (semi-hardy)[13] Mar 20 May 19
Snap beans (tender)[13] Apr 3 Jun 2
Sweet corn (tender)[13] Apr 3 Jun 2
Cucumbers (tender)[13] Apr 3 May 28
Summer squash (tender)[13] Apr 3 May 23
Cantaloupe (very tender)[13] Apr 17 Jul 11
Eggplant (very tender)[13] Apr 17 Jun 16 (from transplants)
Peppers (very tender)[13] Apr 17 Jun 26 (from transplants)
Tomatoes (very tender)[13] Apr 17 Jun 21 (from transplants)
Winter squash (very tender)[13] Apr 17 Jul 26
Watermelon (very tender)[13] Apr 17 Jul 11
Spacing, depth and soil temperature (CSU Extension)
Vegetable Min. soil temp Depth Spacing Days to harvest
Broccoli[14] 40°F 1/2 in 18 in 65
Cabbage[14] 40°F 1/2 in 18 in 85
Kohlrabi[14] 40°F 1/2 in 7-9 in 50
Lettuce[14] 35°F 1/4 in 7-9 in 60
Onions[14] 35°F 1/4 in (seed), 1-2 in (sets) 4-6 in 110
Peas[14] 40°F 1 in 4-6 in 65
Radishes[14] 40°F 1/2 in 2-3 in 30
Spinach[14] 40°F 1/2 in 4-6 in 40
Turnips[14] 40°F 1/2 in 4-6 in 50
Beets[14] 40°F 3/4-1 in 4-6 in 60
Carrots[14] 40°F 1/4 in 2-3 in 70
Cauliflower[14] 40°F 1/2 in 18 in –
Parsnips[14] 35°F 1/2 in 5-6 in 70
Potatoes[14] 45°F – – 125
Swiss chard[14] 40°F 1 in 7-9 in 60
Snap beans[14] 55°F 1-1 1/2 in 6 in 60
Sweet corn[14] 50°F 1-1 1/2 in 12 x 30 in or 9 x 36 in 60-90
Cucumbers[14] 60°F 1 in 6 in trellised, 24-36 in untrellised 55
Summer squash[14] 60°F 1-1 1/2 in 36-48 in 50
Cantaloupe[14] 60°F 1-1 1/2 in 36-48 in 85
Eggplant[14] 60°F 1/4 in 18-24 in 60
Peppers[14] 60°F 1/4 in 15-18 in 70
Tomatoes[14] 50°F 1/4 in 24 in trellised 65
Winter squash[14] 60°F 1-1 1/2 in 36-48 in 100
Watermelon[14] 60°F 1-1 1/2 in 36-48 in 85

Hardiness zone

Zone 8b means the average coldest night of each winter from 1991 to 2020 was 15°F to 20°F[1]. The zone does not describe summer heat or frost dates[15]. Most of Lancaster, 88% of its land area, lies in ZIP code areas rated zone 8b, and 12% lies in areas rated zone 8a[16].

Zone 8b: average annual extreme minimum temperature 15°F to 20°F (1991 to 2020)[1]. Modeled value at the city center: 15°F[1].

Share of the city's land area by ZIP code zone: zone 8b 88%, zone 8a 12%[16].

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

Zone by ZIP code
ZIP code Zone Coldest night range
93536[16] 8b 15 to 20°F
93535[16] 8b 15 to 20°F
93534[16] 8a 10 to 15°F
93551[16] 9a 20 to 25°F

Questions people ask

What growing zone is Lancaster, California?
The center of Lancaster is in USDA zone 8b[1]. About 12% of the city's land area is in ZIP code areas rated zone 8a[16].
When is the last frost in Lancaster?
The median last spring frost is April 3, so in half of years the last frost comes after that date[2]. In 1 of 10 years it comes after April 23[2].
When is the first frost in Lancaster?
The median first fall frost is November 1, so in half of years the first frost comes before that date[3]. In 1 of 10 years it comes before October 17[3].
When to plant tomatoes in Lancaster?
CSU Extension typically suggests 2 or more weeks after the average last frost for tomatoes, which gives an earliest start of April 17[10]. CSU's guide was written for Colorado[10].
How long is the growing season in Lancaster?
The season between the last spring and first fall frost is at least 211 days in half of years[4]. It is at least 185 days in 9 of 10 years[4].

Facts and sources

  1. The 2023 USDA Plant Hardiness Zone Map puts the center of Lancaster, California in zone 8b. Zone 8b means an average annual extreme minimum temperature of 15°F to 20°F over 1991 to 2020. The map's modeled value at the city center is 15°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 8, in half of years after April 3, and in 1 of 10 years after April 23 (NOAA 1991 to 2020 normals). The median last frost date is April 3. 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 November 1, and in 9 of 10 years before November 14 (NOAA 1991 to 2020 normals). The median first frost date is November 1. NOAA Climate Normals 1991-2020
  4. Growing season (days between the last spring and first fall 32°F frost) at this station: at least 185 days in 9 of 10 years, at least 211 days in half of years, and at least 240 days in 1 of 10 years. NOAA Climate Normals 1991-2020
  5. Frost dates on this page come from NOAA climate normals for the Lancaster Wm J Fox Field weather station (USW00003159), 3.9 miles from the center of Lancaster at 2,338 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 8 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 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. Tender and very tender vegetables do not tolerate frost (CSU Extension). In Lancaster the median first fall frost is November 1. CSU Extension GardenNotes #720
  12. 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
  13. 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
  14. CSU Extension vegetable table: soil temperature, depth, spacing, days to harvest (table on this page). CSU Extension GardenNotes #720
  15. 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
  16. Lancaster, California overlaps 4 ZIP code areas. By land area, 88% lies in ZIP code areas rated zone 8b, 12% 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.