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

Planting zone for 93445 — Oceano, CA

ZIP code 93445 (Oceano, San Luis Obispo County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 93445 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 Oceano, 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 Pismo Beach, CA — 9 miles away, elevation 39 ft) the median growing season is 362 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 93445 came on Jan 21 — 3 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 Oceano, CA

The center of ZIP 93445 is mapped as Dune land: built-over ground without natural soil data. Garden soil here is usually imported or disturbed — test before you plant.

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 93445; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Oceano, CA

Summer high73 °Faverage high, October
Winter low44 °Faverage low, January
Hot days4days a year at 90 °F or more
Freezing nights2nights a year at 32 °F or less
Growing degree days3,364base 50 °F — the season’s usable heat
Longest day14 h 31 mindaylight on June 21
Shortest day9 h 48 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation17.9 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 65 °F, low 44 °F 65°44° JanFebruary: average high 65 °F, low 44 °F 65°44° FebMarch: average high 68 °F, low 46 °F 68°46° MarApril: average high 70 °F, low 48 °F 70°48° AprMay: average high 72 °F, low 50 °F 72°50° MayJune: average high 71 °F, low 51 °F 71°51° JunJuly: average high 70 °F, low 54 °F 70°54° JulAugust: average high 71 °F, low 55 °F 71°55° AugSeptember: average high 72 °F, low 54 °F 72°54° SepOctober: average high 73 °F, low 53 °F 73°53° OctNovember: average high 69 °F, low 46 °F 69°46° NovDecember: average high 65 °F, low 44 °F 65°44° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.48 in precipitation 3.5 JanFebruary: 4.00 in precipitation 4.0 FebMarch: 2.98 in precipitation 3.0 MarApril: 1.00 in precipitation 1.0 AprMay: 0.46 in precipitation 0.5 MayJune: 0.15 in precipitation 0.1 JunJuly: 0.02 in precipitation 0.0 JulAugust: 0.02 in precipitation 0.0 AugSeptember: 0.08 in precipitation 0.1 SepOctober: 0.79 in precipitation 0.8 OctNovember: 1.81 in precipitation 1.8 NovDecember: 3.08 in precipitation 3.1 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Pismo Beach, CA (9 mi away); precipitation: Pismo Beach, CA (9 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.

All 2 ZIP codes in Oceano → · California planting zones →

Questions about 93445

What planting zone is ZIP code 93445?

ZIP code 93445 (Oceano, 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 93445 get?

About 17.9 inches of precipitation a year (NOAA 1991–2020 normals, Pismo Beach station).

How hot do summers get in Oceano, CA?

The average high peaks at 73 °F in October, with about 4 days a year at 90 °F or more.

Did spring come early in Oceano, CA in 2026?

Spring leaf-out near 93445 came on Jan 21 in 2026, 3 days earlier than the 1991–2020 average (Jan 24), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Oceano, CA?

Intermediate onions: the longest day near 93445 is 14 h 31 min, so day-neutral types bulb best; long-day varieties may not bulb fully.