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

Planting zone for 92678 — Trabuco Canyon, CA

ZIP code 92678 (Trabuco Canyon, Orange County) is in USDA zone 10b: the coldest winter night averages 35 to 40 °F. The median last spring frost is January 28 and the first fall frost December 18.

Where ZIP 92678 is

Outlined: the ZIP code area · 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.

Zone10b35 to 40 °F
Coldest night1.7 to 4.4 °C
Last frostJan 28
First frostDec 18
2012 zone10a

Was 10a on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 10b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Trabuco Canyon, 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 Trabuco Canyon, CA

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostJanuary 28median — 50% chance of a later frost
Safe for tender plantsFebruary 27only 10% chance of frost after
First fall frostDecember 18median — 10% chance by Dec 1
Growing season329 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 1 and returns around December 27.

From the NOAA station Elsinore, CA — 9 miles away, elevation 1,270 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 92678

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Dec 17 – Dec 31
SpinachSow outdoors · Dec 17 – Jan 7
Broccoli, cabbageStart indoors · Nov 19 – Dec 3
Broccoli, cabbageTransplant · Jan 7 – Jan 21
Onion setsPlant outdoors · Dec 31 – Jan 14
PotatoesPlant outdoors · Jan 7 – Jan 21
LettuceSow outdoors · Dec 31 – Jan 14
Carrots, beetsSow outdoors · Jan 7 – Jan 21
TomatoesStart indoors · Dec 3 – Dec 17
TomatoesTransplant · Feb 4 – Feb 18
Peppers, eggplantStart indoors · Nov 19 – Dec 3
Peppers, eggplantTransplant · Feb 11 – Feb 25
BeansSow outdoors · Feb 4 – Feb 18
Sweet cornSow outdoors · Feb 4 – Feb 18
Cucumbers, squashSow outdoors · Feb 4 – Feb 18
Fall lettuce, spinachSow outdoors · Oct 23 – Nov 6
GarlicPlant cloves · Dec 4 – Jan 8
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Jan 28) and first fall frost (Dec 18) 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 92678 came on Jan 18 — 6 days earlier than the 1991–2020 average (Jan 24).

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 Trabuco Canyon, CA

The soil mapped at the center of ZIP 92678 is Friant — gravelly fine sandy loam, well drained.

TextureGravelly fine sandy loamdrains and warms fast; dries out and needs more feeding
pH6.5neutral; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1.5%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Friant fine sandy loam, 30 to 75 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 92678; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Trabuco Canyon, CA

Summer high98 °Faverage high, August
Winter low40 °Faverage low, December
Hot days123days a year at 90 °F or more
Freezing nights9nights a year at 32 °F or less
Growing degree days5,940base 50 °F — the season’s usable heat
Longest day14 h 23 mindaylight on June 21
Shortest day9 h 55 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation14.4 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°110°32 °FJanuary: average high 66 °F, low 42 °F 66°42° JanFebruary: average high 67 °F, low 43 °F 67°43° FebMarch: average high 72 °F, low 46 °F 72°46° MarApril: average high 77 °F, low 49 °F 77°49° AprMay: average high 82 °F, low 54 °F 82°54° MayJune: average high 90 °F, low 58 °F 90°58° JunJuly: average high 97 °F, low 64 °F 97°64° JulAugust: average high 98 °F, low 65 °F 98°65° AugSeptember: average high 93 °F, low 61 °F 93°61° SepOctober: average high 83 °F, low 54 °F 83°54° OctNovember: average high 73 °F, low 46 °F 73°46° NovDecember: average high 65 °F, low 40 °F 65°40° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.52 in precipitation 3.5 JanFebruary: 3.38 in precipitation 3.4 FebMarch: 1.77 in precipitation 1.8 MarApril: 0.91 in precipitation 0.9 AprMay: 0.28 in precipitation 0.3 MayJune: 0.16 in precipitation 0.2 JunJuly: 0.10 in precipitation 0.1 JulAugust: 0.24 in precipitation 0.2 AugSeptember: 0.26 in precipitation 0.3 SepOctober: 0.46 in precipitation 0.5 OctNovember: 0.77 in precipitation 0.8 NovDecember: 2.57 in precipitation 2.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Elsinore, CA (9 mi away); precipitation: Corona 12.8 Se, CA (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

9267910b
Trabuco Canyon, CA · 3 mi
9268810b
Rancho Santa Margarita, CA · 6 mi
9288310a
Corona, CA · 7 mi
9253010a
Lake Elsinore, CA · 8 mi
9269210b
Mission Viejo, CA · 8 mi
9269010b
Mission Viejo, CA · 8 mi
9261010b
Foothill Ranch, CA · 9 mi
9267610b
Silverado, CA · 9 mi

All 2 ZIP codes in Trabuco Canyon → · California planting zones →

Questions about 92678

What planting zone is ZIP code 92678?

ZIP code 92678 (Trabuco Canyon, CA) is in USDA hardiness zone 10b on the 2023 map: the coldest night of an average winter reaches 35 to 40 °F (1.7 to 4.4 °C).

When is the last frost in Trabuco Canyon, CA?

The median last spring frost (32 °F) near 92678 is January 28; after February 27 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Elsinore station.

When is the first frost in Trabuco Canyon, CA?

The median first fall frost near 92678 is December 18, giving a median frost-free growing season of 329 days.

When should I plant tomatoes in 92678?

Start tomato seeds indoors around Dec 3 – Dec 17 and set transplants outside around Feb 4 – Feb 18, one to three weeks after the median last frost.

How much rain and snow does 92678 get?

About 14.4 inches of precipitation a year (NOAA 1991–2020 normals, Corona 12.8 Se station).

How hot do summers get in Trabuco Canyon, CA?

The average high peaks at 98 °F in August, with about 123 days a year at 90 °F or more.

What kind of soil does 92678 have?

The USDA soil survey maps Friant at the center of ZIP 92678: gravelly fine sandy loam, well drained, pH about 6.5 (neutral).

Did spring come early in Trabuco Canyon, CA in 2026?

Spring leaf-out near 92678 came on Jan 18 in 2026, 6 days earlier than the 1991–2020 average (Jan 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Trabuco Canyon, CA?

Intermediate onions: the longest day near 92678 is 14 h 23 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 92678 change?

Yes. The 2012 USDA map put 92678 in zone 10a; the 2023 map puts it in zone 10b. The newer map uses 1991–2020 data and more weather stations.