Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 92018 — Carlsbad, CA

ZIP code 92018 (Carlsbad, San Diego County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F. The median last spring frost is January 23 and the first fall frost December 11.

Where ZIP 92018 is

tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostJan 23
First frostDec 11
2012 zone10a

Same zone as on the 2012 map. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 10a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Carlsbad, CA…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Carlsbad, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 23median — 50% chance of a later frost
Safe for tender plantsFebruary 22only 10% chance of frost after
First fall frostDecember 11median — 10% chance by Nov 21
Growing season325 daysfrost-free, median

A hard freeze (28 °F) usually ends around December 31 and returns around December 23.

From the NOAA station Oceanside Municipal Airport, CA — 4 miles away, elevation 30 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 92018

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 12 – Dec 26
SpinachSow outdoors · Dec 12 – Jan 2
Broccoli, cabbageStart indoors · Nov 14 – Nov 28
Broccoli, cabbageTransplant · Jan 2 – Jan 16
Onion setsPlant outdoors · Dec 26 – Jan 9
PotatoesPlant outdoors · Jan 2 – Jan 16
LettuceSow outdoors · Dec 26 – Jan 9
Carrots, beetsSow outdoors · Jan 2 – Jan 16
TomatoesStart indoors · Nov 28 – Dec 12
TomatoesTransplant · Jan 30 – Feb 13
Peppers, eggplantStart indoors · Nov 14 – Nov 28
Peppers, eggplantTransplant · Feb 6 – Feb 20
BeansSow outdoors · Jan 30 – Feb 13
Sweet cornSow outdoors · Jan 30 – Feb 13
Cucumbers, squashSow outdoors · Jan 30 – Feb 13
Fall lettuce, spinachSow outdoors · Oct 16 – Oct 30
GarlicPlant cloves · Nov 27 – Jan 1
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 23) and first fall frost (Dec 11) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 92018 came on Jan 19 — 4 days earlier than the 1991–2020 average (Jan 23).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Soil in Carlsbad, CA

The soil mapped at the center of ZIP 92018 is Marina — loamy coarse sand, somewhat excessively drained.

TextureLoamy coarse sanddrains and warms fast; dries out and needs more feeding
pH6.5neutral; most vegetables like 6.0–7.0
DrainageSomewhat excessively drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Marina loamy coarse sand, 2 to 9 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 92018; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Carlsbad, CA

Summer high78 °Faverage high, August
Winter low40 °Faverage low, December
Hot days5days a year at 90 °F or more
Freezing nights8nights a year at 32 °F or less
Growing degree days4,072base 50 °F — the season’s usable heat
Longest day14 h 21 mindaylight on June 21
Shortest day9 h 57 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation13.5 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°32 °FJanuary: average high 67 °F, low 41 °F 67°41° JanFebruary: average high 66 °F, low 42 °F 66°42° FebMarch: average high 66 °F, low 46 °F 66°46° MarApril: average high 69 °F, low 48 °F 69°48° AprMay: average high 70 °F, low 54 °F 70°54° MayJune: average high 73 °F, low 58 °F 73°58° JunJuly: average high 77 °F, low 62 °F 77°62° JulAugust: average high 78 °F, low 62 °F 78°62° AugSeptember: average high 78 °F, low 59 °F 78°59° SepOctober: average high 75 °F, low 53 °F 75°53° OctNovember: average high 71 °F, low 44 °F 71°44° NovDecember: average high 66 °F, low 40 °F 66°40° Dec

Precipitation by month inches

0″1″2″3″January: 2.68 in precipitation 2.7 JanFebruary: 2.98 in precipitation 3.0 FebMarch: 1.83 in precipitation 1.8 MarApril: 1.00 in precipitation 1.0 AprMay: 0.32 in precipitation 0.3 MayJune: 0.10 in precipitation 0.1 JunJuly: 0.07 in precipitation 0.1 JulAugust: 0.02 in precipitation 0.0 AugSeptember: 0.20 in precipitation 0.2 SepOctober: 0.61 in precipitation 0.6 OctNovember: 1.18 in precipitation 1.2 NovDecember: 2.53 in precipitation 2.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oceanside Municipal Airport, CA (4 mi away); precipitation: Carlsbad 1.3ene, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

1 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

9201310b
Carlsbad, CA · <1 mi
9200810a
Carlsbad, CA · 2 mi
9205410a
Oceanside, CA · 2 mi
9204910a
Oceanside, CA · 3 mi
9205110a
Oceanside, CA · 3 mi
9205210a
Oceanside, CA · 3 mi
9201010a
Carlsbad, CA · 4 mi
9205610a
Oceanside, CA · 4 mi

All 6 ZIP codes in Carlsbad → · California planting zones →

Questions about 92018

What planting zone is ZIP code 92018?

ZIP code 92018 (Carlsbad, CA) is in USDA hardiness zone 10a on the 2023 map: the coldest night of an average winter reaches 30 to 35 °F (−1.1 to 1.7 °C).

When is the last frost in Carlsbad, CA?

The median last spring frost (32 °F) near 92018 is January 23; after February 22 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Oceanside Municipal Airport station.

When is the first frost in Carlsbad, CA?

The median first fall frost near 92018 is December 11, giving a median frost-free growing season of 325 days.

When should I plant tomatoes in 92018?

Start tomato seeds indoors around Nov 28 – Dec 12 and set transplants outside around Jan 30 – Feb 13, one to three weeks after the median last frost.

How much rain and snow does 92018 get?

About 13.5 inches of precipitation a year (NOAA 1991–2020 normals, Carlsbad 1.3ene station).

How hot do summers get in Carlsbad, CA?

The average high peaks at 78 °F in August, with about 5 days a year at 90 °F or more.

What kind of soil does 92018 have?

The USDA soil survey maps Marina at the center of ZIP 92018: loamy coarse sand, somewhat excessively drained, pH about 6.5 (neutral).

Did spring come early in Carlsbad, CA in 2026?

Spring leaf-out near 92018 came on Jan 19 in 2026, 4 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Carlsbad, CA?

Intermediate onions: the longest day near 92018 is 14 h 21 min, so day-neutral types bulb best; long-day varieties may not bulb fully.