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

Planting zone for 92627 — Costa Mesa, CA

ZIP code 92627 (Costa Mesa, Orange County) is in USDA zone 10b: the coldest winter night averages 35 to 40 °F.

Where ZIP 92627 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 frostrare
First frostrare
2012 zone10b

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 10b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Costa Mesa, 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

A 32 °F frost doesn't happen here in most winters. At the nearest station (NOAA station Tustin Irvine Rch, CA — 11 miles away, elevation 236 ft) the median growing season is 365 days. When frost does come, it is a midwinter night or two; cover tender plants when a freeze is forecast.

Frost data: NOAA NCEI U.S. Climate Normals 1991–2020.

When spring arrived in 2026

In 2026, spring leaf-out near 92627 came on Jan 17 — 4 days earlier than the 1991–2020 average (Jan 21).

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 Costa Mesa, CA

The soil mapped at the center of ZIP 92627 is Myford — sandy loam, moderately well drained.

TextureSandy loamdrains and warms fast; dries out and needs more feeding
pH5.6moderately acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Myford sandy loam, 0 to 2 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 92627; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Costa Mesa, CA

Summer high74 °Faverage high, September
Winter low50 °Faverage low, January
Hot days1days a year at 90 °F or more
Freezing nights0nights a year at 32 °F or less
Growing degree days4,668base 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
Precipitation9.4 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°January: average high 65 °F, low 50 °F 65°50° JanFebruary: average high 63 °F, low 51 °F 63°51° FebMarch: average high 65 °F, low 53 °F 65°53° MarApril: average high 66 °F, low 55 °F 66°55° AprMay: average high 67 °F, low 58 °F 67°58° MayJune: average high 68 °F, low 62 °F 68°62° JunJuly: average high 72 °F, low 65 °F 72°65° JulAugust: average high 73 °F, low 66 °F 73°66° AugSeptember: average high 74 °F, low 64 °F 74°64° SepOctober: average high 73 °F, low 60 °F 73°60° OctNovember: average high 68 °F, low 55 °F 68°55° NovDecember: average high 64 °F, low 50 °F 64°50° Dec

Precipitation by month inches

0″1″2″3″January: 2.20 in precipitation 2.2 JanFebruary: 2.38 in precipitation 2.4 FebMarch: 1.34 in precipitation 1.3 MarApril: 0.55 in precipitation 0.6 AprMay: 0.18 in precipitation 0.2 MayJune: 0.07 in precipitation 0.1 JunJuly: 0.02 in precipitation 0.0 JulAugust: 0.00 in precipitation 0.0 AugSeptember: 0.10 in precipitation 0.1 SepOctober: 0.33 in precipitation 0.3 OctNovember: 0.64 in precipitation 0.6 NovDecember: 1.62 in precipitation 1.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Newport Beach Harbor, CA (4 mi away); precipitation: Newport Beach Harbor, CA (4 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10b.

9262810b
Costa Mesa, CA · <1 mi
9266310b
Newport Beach, CA · 2 mi
9265910b
Newport Beach, CA · 2 mi
9262610b
Costa Mesa, CA · 2 mi
9266010b
Newport Beach, CA · 3 mi
9264610b
Huntington Beach, CA · 3 mi
9261510b
Huntington Beach, CA · 3 mi
9266110b
Newport Beach, CA · 3 mi

All 3 ZIP codes in Costa Mesa → · California planting zones →

Questions about 92627

What planting zone is ZIP code 92627?

ZIP code 92627 (Costa Mesa, 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).

How much rain and snow does 92627 get?

About 9.4 inches of precipitation a year (NOAA 1991–2020 normals, Newport Beach Harbor station).

How hot do summers get in Costa Mesa, CA?

The average high peaks at 74 °F in September, with about 1 days a year at 90 °F or more.

What kind of soil does 92627 have?

The USDA soil survey maps Myford at the center of ZIP 92627: sandy loam, moderately well drained, pH about 5.6 (moderately acidic).

Did spring come early in Costa Mesa, CA in 2026?

Spring leaf-out near 92627 came on Jan 17 in 2026, 4 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Costa Mesa, CA?

Intermediate onions: the longest day near 92627 is 14 h 23 min, so day-neutral types bulb best; long-day varieties may not bulb fully.