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Planting zones · San Francisco Bay Area, California

What Planting Zone Is San Francisco Bay Area?

San Francisco Bay Area is in USDA zone 9b–10b. Mediterranean climate with strong microclimates: San Francisco gets about 23 in. of rain and did not reach 32°F in the 1991–2020 normals, while San Jose gets about 13.5 in. and freezes in roughly three winters out of four. Nearly all rain falls November–March.

  • USDA zone (2023)9b–10b
  • Coldest night (avg.)35 to 40°FZIP 94102
  • Annual precipitation23 inches

San Francisco Bay Area hardiness zone by ZIP code

On the 2023 USDA Plant Hardiness Zone Map, the ZIP codes we sampled in San Francisco Bay Area fall in zones 9b to 10b; 94102 (zone 10b) has an average annual extreme minimum of 35 to 40°F. Choose perennials, shrubs, and trees rated at least to zone 9 if you live in one of the colder ZIPs.

2023 USDA zone for sampled San Francisco Bay Area ZIP codes
ZIPZoneAvg. coldest night
9410210b35 to 40°F
9411010b35 to 40°F
945969b25 to 30°F
9461210a30 to 35°F
951129b25 to 30°F

Not listed? Look up any ZIP code.

Frost dates and when to plant

NOAA's 1991–2020 normals recorded no 32°F freeze at San Francisco Downtown, so there are no meaningful frost dates; colder inland and valley neighborhoods can still see light frost.

With frost rare, you can plant most of the year; fall and winter plantings benefit from the rainy season.

Rainfall and heat in San Francisco Bay Area

Average annual precipitation is 23 inches (San Francisco Downtown, 1991–2020), and 84% of it falls November–March. Summers are dry (July is the driest month), so plants lean on stored soil moisture and supplemental water through their first summer.

The average high in September is about 70°F and the average low in January is about 47°F, measured at about 150 ft.

That is why a zone rating alone isn't enough for a xeriscape here: pick plants that are both cold-hardy to zone 9 and rated very low or low water once established.

Low-water plants for San Francisco Bay Area

18 plants in our database are hardy to zone 9 and suited to zone 10. Here are 12, driest first, across plant types.

See all zone 10 plants

Frequently asked questions

What planting zone is San Francisco Bay Area?

San Francisco Bay Area, CA is in USDA hardiness zone 9b–10b on the 2023 USDA Plant Hardiness Zone Map, based on the ZIP codes we sampled (94102: 10b, 94110: 10b, 94596: 9b, 94612: 10a, 95112: 9b). In 94102, the average coldest night of the year is 35 to 40°F.

When is the last frost in San Francisco Bay Area?

NOAA's 1991–2020 normals recorded no 32°F freeze at San Francisco Downtown, so there are no meaningful frost dates; colder inland and valley neighborhoods can still see light frost.

How much rain does San Francisco Bay Area get?

Average annual precipitation is 23 inches (San Francisco Downtown, 1991–2020), and 84% of it falls November–March. Summers are dry (July is the driest month), so plants lean on stored soil moisture and supplemental water through their first summer.

Sources

  1. NOAA NCEI U.S. Climate Normals 1991–2020, San Francisco Downtown (USW00023272). ncei.noaa.gov
  2. NOAA NCEI U.S. Climate Normals 1991–2020, San Jose (USW00023293). ncei.noaa.gov
  3. USDA ARS 2023 Plant Hardiness Zone Map, by ZIP. planthardiness.ars.usda.gov