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

Planting zone for 94497 — San Mateo, CA

ZIP code 94497 (San Mateo, San Mateo County) is in USDA zone 10a: the coldest winter night averages 30 to 35 °F.

Where ZIP 94497 is

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 Mateo, 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 Redwood City, CA — 6 miles away, elevation 30 ft) the median growing season is 333 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 94497 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 Mateo, CA

The soil mapped at the center of ZIP 94497 is Los Gatos — slightly decomposed plant material, well drained.

TextureSlightly decomposed plant materialtop layer
DrainageWell drainednatural drainage class
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Los Gatos loam, 30 to 75 percent slopes, MLRA 15.

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 94497; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in San Mateo, CA

Summer high81 °Faverage high, July
Winter low40 °Faverage low, December
Hot days18days a year at 90 °F or more
Freezing nights6nights a year at 32 °F or less
Growing degree days3,606base 50 °F — the season’s usable heat
Longest day14 h 45 mindaylight on June 21
Shortest day9 h 34 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation25.7 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°32 °FJanuary: average high 59 °F, low 41 °F 59°41° JanFebruary: average high 62 °F, low 43 °F 62°43° FebMarch: average high 65 °F, low 45 °F 65°45° MarApril: average high 69 °F, low 47 °F 69°47° AprMay: average high 73 °F, low 50 °F 73°50° MayJune: average high 79 °F, low 54 °F 79°54° JunJuly: average high 81 °F, low 57 °F 81°57° JulAugust: average high 81 °F, low 57 °F 81°57° AugSeptember: average high 79 °F, low 54 °F 79°54° SepOctober: average high 75 °F, low 50 °F 75°50° OctNovember: average high 65 °F, low 44 °F 65°44° NovDecember: average high 59 °F, low 40 °F 59°40° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.65 in precipitation 4.7 JanFebruary: 4.40 in precipitation 4.4 FebMarch: 4.26 in precipitation 4.3 MarApril: 2.26 in precipitation 2.3 AprMay: 0.74 in precipitation 0.7 MayJune: 0.18 in precipitation 0.2 JunJuly: 0.01 in precipitation 0.0 JulAugust: 0.06 in precipitation 0.1 AugSeptember: 0.13 in precipitation 0.1 SepOctober: 1.02 in precipitation 1.0 OctNovember: 2.51 in precipitation 2.5 NovDecember: 5.49 in precipitation 5.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Redwood City, CA (6 mi away); precipitation: San Mateo 3.4 Ssw, CA (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 10a.

9440210a
San Mateo, CA · <1 mi
9440310a
San Mateo, CA · 1 mi
9400210a
Belmont, CA · 2 mi
9440110a
San Mateo, CA · 3 mi
9440410a
San Mateo, CA · 4 mi
9401010a
Burlingame, CA · 4 mi
9407010a
San Carlos, CA · 4 mi
9401110a
Burlingame, CA · 4 mi

All 5 ZIP codes in San Mateo → · California planting zones →

Questions about 94497

What planting zone is ZIP code 94497?

ZIP code 94497 (San Mateo, 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 94497 get?

About 25.7 inches of precipitation a year (NOAA 1991–2020 normals, San Mateo 3.4 Ssw station).

How hot do summers get in San Mateo, CA?

The average high peaks at 81 °F in July, with about 18 days a year at 90 °F or more.

What kind of soil does 94497 have?

The USDA soil survey maps Los Gatos at the center of ZIP 94497: slightly decomposed plant material, well drained.

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

Spring leaf-out near 94497 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 Mateo, CA?

Intermediate onions: the longest day near 94497 is 14 h 45 min, so day-neutral types bulb best; long-day varieties may not bulb fully.