When is the last frost in Lompoc, CA?

The average last spring frost (50% probability of 32°F) in Lompoc is around January 20, based on NOAA/NCEI 1991–2020 normals at the Lompoc, CA station (8.1 mi away). Half of years it falls outside that date, so wait 1–2 weeks past it before setting out frost-tender plants.

When is the first fall frost in Lompoc?

The average first fall frost in Lompoc, CA is around December 19, giving roughly a 335-day frost-free growing season.

What planting zone is Lompoc, CA?

Lompoc is in USDA plant hardiness zone 10a (average annual extreme minimum temperature 30 to 35°F), from the 2023 USDA Plant Hardiness Zone Map.

What is the weather like in Lompoc?

In Lompoc, CA the warmest month is September (avg high 74.8°F) and the coldest is December (avg low 42.1°F). It averages about 15.4″ of precipitation a year.

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Lompoc, CA Planting Calendar & Frost Dates

USDA hardiness zone 10a · ZIP 93437 · elevation 23′ · NOAA & USDA data

Lompoc is in USDA hardiness zone 10a (winters can dip to 30 to 35°F), with a growing season of about 335 days between the average last spring frost (January 20) and first fall frost (December 19). The warmest month is September (avg high 74.8°F); the coldest is December (avg low 42.1°F). It averages 15.4″ of precipitation a year. Start cool-season crops several weeks before the last frost; wait until after it for tomatoes, peppers and other tender crops.

Hardiness zone

10a

min temp 30 to 35°F

Last spring frost

January 20

avg (50% prob, 32°F)

First fall frost

December 19

avg (50% prob, 32°F)

Growing season

335 days

frost-free window

Warmest month

September

avg high 74.8°F

Month-by-month typical weather in Lompoc

Average conditions from the NOAA/NCEI 1991–2020 U.S. Climate Normals at Lompoc, CA (8.1 mi away). Temperatures °F, precipitation & snow in inches.

Month	Avg high	Avg low	Mean	Precip (in)
January	64.7	43.2	54	3.3
February	65.1	44.2	54.6	3.7
March	67.3	46	56.6	2.8
April	68.2	47.4	57.8	0.9
May	69.2	50.6	59.9	0.3
June	70.7	52.9	61.8	0.1
July	72.5	55.5	64	0
August	73.3	56	64.6	0
September	74.8	54.9	64.8	0.1
October	74.1	51.1	62.6	0.7
November	69.6	46	57.8	1.2
December	63.3	42.1	52.7	2.4

What to plant when in Lompoc

Crop	Season	What to do & when
Tomatoes	warm	Start seeds indoors: December 9 · Transplant out: January 27
Peppers	warm	Start seeds indoors: November 25 · Transplant out: February 3
Cucumbers	warm	Direct sow: January 27
Zucchini / squash	warm	Direct sow: January 27
Bush beans	warm	Direct sow: January 27
Sweet corn	warm	Direct sow: January 27
Basil	warm	Transplant out: January 27
Peas	cool	Sow (spring): December 16 · Sow (fall): October 24
Spinach	cool	Sow (spring): December 9 · Sow (fall): October 24
Lettuce	cool	Sow (spring): December 23 · Sow (fall): October 24
Kale	cool	Transplant (spring): December 30 · Sow (fall): October 10
Broccoli	cool	Transplant (spring): January 6
Carrots	cool	Sow (spring): December 30 · Sow (fall): October 10
Onions	cool	Transplant (spring): December 23
Potatoes	cool	Plant seed potatoes: January 6
Radishes	cool	Sow (spring): December 23 · Sow (fall): November 7

Dates are computed from Lompoc's average frost dates using standard cool-/warm-season timing. They're a starting point — a cold spring, a warm microclimate, or a fast-maturing variety can shift them by a week or two.

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Gear that helps you plant on time

Some links below are Amazon affiliate links (tag theboringthin-20). If you buy through them we may earn a small commission at no extra cost to you — it keeps this almanac free. We only list generic, genuinely-useful categories.

Soil thermometer →Know when the ground is warm enough to sow — the honest signal, not the calendar.Seed-starting trays + dome →Start tomatoes & peppers indoors on the schedule below.Seedling heat mat →Warms the soil for faster, more even germination indoors.Floating row cover / frost cloth →Buys you 4–8°F to beat an early or late frost.Raised garden bed kit →Warms and drains faster in spring than in-ground soil.Garden gloves →Basic kit for transplant day.

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Sources & method. Hardiness zone: 2023 USDA Plant Hardiness Zone Map (PRISM Climate Group, Oregon State University). Frost dates & growing season: NOAA/NCEI 1991–2020 U.S. Climate Normals, nearest station with published freeze normals — Lompoc, CA, 8.1 mi (confidence: high). Monthly weather normals: Lompoc, CA, 8.1 mi (confidence: high). ZIP centroid from U.S. Census 2023 ZCTA data. Frost dates are the 50%-probability date — half of years frost occurs outside the stated date. Nothing here is invented; where the nearest station is far, we say so. Last updated 2026-07-22.