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

Planting zone for 94577 — San Leandro, CA

ZIP code 94577 (San Leandro, Alameda County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 94577 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 San Leandro, 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 Oakland Metro Intl Airport, CA — 3 miles away, elevation 7 ft) the median growing season is 356 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 94577 came on Jan 26 — about the same time as the 1991–2020 average (Jan 27).

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 Leandro, CA

The soil mapped at the center of ZIP 94577 is Botella — loam, well drained.

TextureLoama good balance for most vegetables
pH6.0slightly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter4%moderate
Hydrologic groupCwater soaks in slowly
Farmland classPrime farmland if irrigatedUSDA classification

Map unit: Botella loam, 0 to 2 percent slopes, MLRA 14.

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 94577; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Leandro, CA

Summer high74 °Faverage high, September
Winter low42 °Faverage low, January
Hot days6days a year at 90 °F or more
Freezing nights3nights a year at 32 °F or less
Growing degree days3,106base 50 °F — the season’s usable heat
Longest day14 h 47 mindaylight on June 21
Shortest day9 h 33 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation18.7 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°32 °FJanuary: average high 58 °F, low 42 °F 58°42° JanFebruary: average high 60 °F, low 45 °F 60°45° FebMarch: average high 63 °F, low 47 °F 63°47° MarApril: average high 66 °F, low 49 °F 66°49° AprMay: average high 68 °F, low 52 °F 68°52° MayJune: average high 71 °F, low 54 °F 71°54° JunJuly: average high 72 °F, low 56 °F 72°56° JulAugust: average high 72 °F, low 57 °F 72°57° AugSeptember: average high 74 °F, low 56 °F 74°56° SepOctober: average high 72 °F, low 51 °F 72°51° OctNovember: average high 64 °F, low 46 °F 64°46° NovDecember: average high 58 °F, low 42 °F 58°42° Dec

Precipitation by month inches

0″1″2″3″4″January: 3.42 in precipitation 3.4 JanFebruary: 3.51 in precipitation 3.5 FebMarch: 2.71 in precipitation 2.7 MarApril: 1.35 in precipitation 1.4 AprMay: 0.63 in precipitation 0.6 MayJune: 0.18 in precipitation 0.2 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.04 in precipitation 0.0 AugSeptember: 0.10 in precipitation 0.1 SepOctober: 0.88 in precipitation 0.9 OctNovember: 2.02 in precipitation 2.0 NovDecember: 3.84 in precipitation 3.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Oakland Metro Intl Airport, CA (3 mi away); precipitation: Oakland Metro Intl Airport, CA (3 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.

9460310a
Oakland, CA · 2 mi
9461410a
Oakland, CA · 2 mi
9457910a
San Leandro, CA · 2 mi
9457810a
San Leandro, CA · 2 mi
946059b
Oakland, CA · 3 mi
9462110a
Oakland, CA · 3 mi
9458010a
San Lorenzo, CA · 3 mi
945469b
Castro Valley, CA · 4 mi

All 3 ZIP codes in San Leandro → · California planting zones →

Questions about 94577

What planting zone is ZIP code 94577?

ZIP code 94577 (San Leandro, 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 94577 get?

About 18.7 inches of precipitation a year (NOAA 1991–2020 normals, Oakland Metro Intl Airport station).

How hot do summers get in San Leandro, CA?

The average high peaks at 74 °F in September, with about 6 days a year at 90 °F or more.

What kind of soil does 94577 have?

The USDA soil survey maps Botella at the center of ZIP 94577: loam, well drained, pH about 6.0 (slightly acidic).

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

Spring leaf-out near 94577 came on Jan 26 in 2026, about the same as the 1991–2020 average (Jan 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in San Leandro, CA?

Intermediate onions: the longest day near 94577 is 14 h 47 min, so day-neutral types bulb best; long-day varieties may not bulb fully.