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

Planting zone for 92620 — Irvine, CA

ZIP code 92620 (Irvine, Orange County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 92620 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.

Zone10a30 to 35 °F
Coldest night−1.1 to 1.7 °C
Last frostrare
First frostrare
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 Irvine, 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 — within 1 mile, 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 92620 came on Jan 16 — 5 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 Irvine, CA

The soil mapped at the center of ZIP 92620 is San Emigdio — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH8.2alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupAwater soaks in fast
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: San Emigdio fine 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 92620; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Irvine, CA

Summer high87 °Faverage high, August
Winter low43 °Faverage low, January
Hot days35days a year at 90 °F or more
Freezing nights2nights a year at 32 °F or less
Growing degree days5,449base 50 °F — the season’s usable heat
Longest day14 h 24 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
Precipitation14.1 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 68 °F, low 43 °F 68°43° JanFebruary: average high 69 °F, low 45 °F 69°45° FebMarch: average high 72 °F, low 48 °F 72°48° MarApril: average high 74 °F, low 50 °F 74°50° AprMay: average high 77 °F, low 55 °F 77°55° MayJune: average high 80 °F, low 58 °F 80°58° JunJuly: average high 85 °F, low 61 °F 85°61° JulAugust: average high 87 °F, low 63 °F 87°63° AugSeptember: average high 87 °F, low 61 °F 87°61° SepOctober: average high 84 °F, low 55 °F 84°55° OctNovember: average high 76 °F, low 47 °F 76°47° NovDecember: average high 70 °F, low 43 °F 70°43° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.09 in precipitation 3.1 JanFebruary: 3.39 in precipitation 3.4 FebMarch: 2.11 in precipitation 2.1 MarApril: 0.80 in precipitation 0.8 AprMay: 0.32 in precipitation 0.3 MayJune: 0.09 in precipitation 0.1 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.00 in precipitation 0.0 AugSeptember: 0.18 in precipitation 0.2 SepOctober: 0.67 in precipitation 0.7 OctNovember: 1.21 in precipitation 1.2 NovDecember: 2.25 in precipitation 2.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Tustin Irvine Rch, CA (within 1 mile); precipitation: Tustin Irvine Rch, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

9265010b
East Irvine, CA · 2 mi
9260410a
Irvine, CA · 2 mi
9260210b
Irvine, CA · 2 mi
9261910b
Irvine, CA · 3 mi
9278210a
Tustin, CA · 3 mi
9261810b
Irvine, CA · 3 mi
9262310b
Irvine, CA · 3 mi
9278110a
Tustin, CA · 4 mi

All 13 ZIP codes in Irvine → · California planting zones →

Questions about 92620

What planting zone is ZIP code 92620?

ZIP code 92620 (Irvine, 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).

How much rain and snow does 92620 get?

About 14.1 inches of precipitation a year (NOAA 1991–2020 normals, Tustin Irvine Rch station).

How hot do summers get in Irvine, CA?

The average high peaks at 87 °F in August, with about 35 days a year at 90 °F or more.

What kind of soil does 92620 have?

The USDA soil survey maps San Emigdio at the center of ZIP 92620: fine sandy loam, well drained, pH about 8.2 (alkaline).

Did spring come early in Irvine, CA in 2026?

Spring leaf-out near 92620 came on Jan 16 in 2026, 5 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Irvine, CA?

Intermediate onions: the longest day near 92620 is 14 h 24 min, so day-neutral types bulb best; long-day varieties may not bulb fully.