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

Planting zone for 92103 — San Diego, CA

ZIP code 92103 (San Diego, San Diego County) is in USDA zone 10b: the coldest winter night averages 35 to 40 °F.

Where ZIP 92103 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 San Diego, 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 El Cajon, CA — 14 miles away, elevation 495 ft) the median growing season is 350 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 92103 came on Jan 18 — 3 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 San Diego, CA

The soil mapped at the center of ZIP 92103 is Gaviota — fine sandy loam, well drained.

TextureFine sandy loamdrains and warms fast; dries out and needs more feeding
pH7.6slightly alkaline; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter0.75%low — add compost
Hydrologic groupDwater soaks in very slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Gaviota fine sandy loam, 9 to 30 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 92103; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Diego, CA

Summer high77 °Faverage high, August
Winter low50 °Faverage low, January
Hot days3days a year at 90 °F or more
Freezing nights0nights a year at 32 °F or less
Growing degree days5,379base 50 °F — the season’s usable heat
Longest day14 h 19 mindaylight on June 21
Shortest day9 h 59 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation9.8 inper year, rain and melted snow

Average high and low, by month

40°50°60°70°80°90°January: average high 66 °F, low 50 °F 66°50° JanFebruary: average high 66 °F, low 52 °F 66°52° FebMarch: average high 67 °F, low 55 °F 67°55° MarApril: average high 69 °F, low 57 °F 69°57° AprMay: average high 70 °F, low 60 °F 70°60° MayJune: average high 72 °F, low 63 °F 72°63° JunJuly: average high 75 °F, low 66 °F 75°66° JulAugust: average high 77 °F, low 68 °F 77°68° AugSeptember: average high 77 °F, low 66 °F 77°66° SepOctober: average high 75 °F, low 62 °F 75°62° OctNovember: average high 71 °F, low 55 °F 71°55° NovDecember: average high 66 °F, low 50 °F 66°50° Dec

Precipitation by month inches

0″1″2″3″January: 1.98 in precipitation 2.0 JanFebruary: 2.20 in precipitation 2.2 FebMarch: 1.46 in precipitation 1.5 MarApril: 0.65 in precipitation 0.7 AprMay: 0.28 in precipitation 0.3 MayJune: 0.05 in precipitation 0.1 JunJuly: 0.08 in precipitation 0.1 JulAugust: 0.01 in precipitation 0.0 AugSeptember: 0.12 in precipitation 0.1 SepOctober: 0.50 in precipitation 0.5 OctNovember: 0.79 in precipitation 0.8 NovDecember: 1.67 in precipitation 1.7 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: San Diego Lindbergh Field, CA (within 1 mile); precipitation: San Diego Lindbergh Field, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

9219910a
San Diego, CA · 1 mi
9214011a
San Diego, CA · 2 mi
9210111a
San Diego, CA · 2 mi
9211010b
San Diego, CA · 2 mi
9210810b
San Diego, CA · 2 mi
9211210b
San Diego, CA · 2 mi
9213811a
San Diego, CA · 2 mi
9214210b
San Diego, CA · 2 mi

All 73 ZIP codes in San Diego → · California planting zones →

Questions about 92103

What planting zone is ZIP code 92103?

ZIP code 92103 (San Diego, 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 92103 get?

About 9.8 inches of precipitation a year (NOAA 1991–2020 normals, San Diego Lindbergh Field station).

How hot do summers get in San Diego, CA?

The average high peaks at 77 °F in August, with about 3 days a year at 90 °F or more.

What kind of soil does 92103 have?

The USDA soil survey maps Gaviota at the center of ZIP 92103: fine sandy loam, well drained, pH about 7.6 (slightly alkaline).

Did spring come early in San Diego, CA in 2026?

Spring leaf-out near 92103 came on Jan 18 in 2026, 3 days earlier than the 1991–2020 average (Jan 21), according to the USA National Phenology Network Spring Index.

What kind of onions grow in San Diego, CA?

Intermediate onions: the longest day near 92103 is 14 h 19 min, so day-neutral types bulb best; long-day varieties may not bulb fully.