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

Planting zone for 95131 — San Jose, CA

ZIP code 95131 (San Jose, Santa Clara County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 95131 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 zone9b

Was 9b on the 2012 map — half a zone warmer now. 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 Jose, 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 San Jose, CA — 2 miles away, elevation 52 ft) the median growing season is 347 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 95131 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 Jose, CA

The soil mapped at the center of ZIP 95131 is Elpaloalto — slightly decomposed plant material, well drained. Much of the area is built over (urban land); this is the natural soil underneath.

TextureSlightly decomposed plant materialtop layer
pH5.0strongly acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter75%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Urban land-Elpaloalto complex, 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 95131; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Jose, CA

Summer high81 °Faverage high, July
Winter low42 °Faverage low, January
Hot days16days a year at 90 °F or more
Freezing nights3nights a year at 32 °F or less
Growing degree days4,040base 50 °F — the season’s usable heat
Longest day14 h 45 mindaylight on June 21
Shortest day9 h 35 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation13.5 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°32 °FJanuary: average high 60 °F, low 42 °F 60°42° JanFebruary: average high 62 °F, low 44 °F 62°44° FebMarch: average high 66 °F, low 46 °F 66°46° MarApril: average high 69 °F, low 48 °F 69°48° AprMay: average high 74 °F, low 52 °F 74°52° MayJune: average high 79 °F, low 56 °F 79°56° JunJuly: average high 81 °F, low 58 °F 81°58° JulAugust: average high 81 °F, low 59 °F 81°59° AugSeptember: average high 81 °F, low 57 °F 81°57° SepOctober: average high 76 °F, low 53 °F 76°53° OctNovember: average high 66 °F, low 46 °F 66°46° NovDecember: average high 60 °F, low 42 °F 60°42° Dec

Precipitation by month inches

0″1″2″3″January: 2.80 in precipitation 2.8 JanFebruary: 2.69 in precipitation 2.7 FebMarch: 2.08 in precipitation 2.1 MarApril: 1.07 in precipitation 1.1 AprMay: 0.39 in precipitation 0.4 MayJune: 0.18 in precipitation 0.2 JunJuly: 0.00 in precipitation 0.0 JulAugust: 0.05 in precipitation 0.1 AugSeptember: 0.07 in precipitation 0.1 SepOctober: 0.53 in precipitation 0.5 OctNovember: 1.33 in precipitation 1.3 NovDecember: 2.29 in precipitation 2.3 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: San Jose, CA (2 mi away); precipitation: San Jose, CA (2 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

All 55 ZIP codes in San Jose → · California planting zones →

Questions about 95131

What planting zone is ZIP code 95131?

ZIP code 95131 (San Jose, 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 95131 get?

About 13.5 inches of precipitation a year (NOAA 1991–2020 normals, San Jose station).

How hot do summers get in San Jose, CA?

The average high peaks at 81 °F in July, with about 16 days a year at 90 °F or more.

What kind of soil does 95131 have?

The USDA soil survey maps Elpaloalto at the center of ZIP 95131: slightly decomposed plant material, well drained, pH about 5.0 (strongly acidic).

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

Spring leaf-out near 95131 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 Jose, CA?

Intermediate onions: the longest day near 95131 is 14 h 45 min, so day-neutral types bulb best; long-day varieties may not bulb fully.

Did the zone for 95131 change?

Yes. The 2012 USDA map put 95131 in zone 9b; the 2023 map puts it in zone 10a. The newer map uses 1991–2020 data and more weather stations.