Planting zone for 90731 — San Pedro, CA
ZIP code 90731 (San Pedro, Los Angeles County) is in USDA zone 10b: the coldest winter night averages 35 to 40 °F.
Where ZIP 90731 is
Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoomNot 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.
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 ServiceLoading the forecast for San Pedro, 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 Torrance Airport, CA — 6 miles away, elevation 89 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 90731 came on Jan 15 — 5 days earlier than the 1991–2020 average (Jan 20).
Jan 202026
Jan 15
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 Pedro, CA
The soil mapped at the center of ZIP 90731 is Xerorthents — loam, somewhat excessively drained. Much of the area is built over (urban land); this is the natural soil underneath.
Map unit: Urban land, 0 to 2 percent slopes, dredged fill substratum.
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 90731; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.
Climate in San Pedro, CA
Average high and low, by month
Precipitation by month inches
NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Torrance Airport, CA (6 mi away); precipitation: Torrance 2.8 Sw, CA (5 mi away). 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.
All 4 ZIP codes in San Pedro → · California planting zones →
Questions about 90731
What planting zone is ZIP code 90731?
ZIP code 90731 (San Pedro, 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 90731 get?
About 14.2 inches of precipitation a year (NOAA 1991–2020 normals, Torrance 2.8 Sw station).
How hot do summers get in San Pedro, CA?
The average high peaks at 78 °F in August, with about 6 days a year at 90 °F or more.
What kind of soil does 90731 have?
The USDA soil survey maps Xerorthents at the center of ZIP 90731: loam, somewhat excessively drained, pH about 7.4 (slightly alkaline).
Did spring come early in San Pedro, CA in 2026?
Spring leaf-out near 90731 came on Jan 15 in 2026, 5 days earlier than the 1991–2020 average (Jan 20), according to the USA National Phenology Network Spring Index.
What kind of onions grow in San Pedro, CA?
Intermediate onions: the longest day near 90731 is 14 h 24 min, so day-neutral types bulb best; long-day varieties may not bulb fully.