Gardening in San Francisco-Oakland-Fremont, CA
This metro spans USDA zones 9b to 10b, so there is no single zone for San Francisco-Oakland-Fremont, CA and anyone who gives you one is rounding. 44% of its ZIP codes are zone 10a; the rest are not.
Which zone you are in depends where you are
San Francisco-Oakland-Fremont, CA covers 3 hardiness zones. A guide that gives the metro one zone has picked whichever is largest and rounded everyone else into it — which is fine for the 44% in zone 10a and wrong for the other 56%. Here is the actual split.
| Zone | ZIP codes | Share | |
|---|---|---|---|
| 10a | 79 | 44% | |
| 9b | 72 | 40% | |
| 10b | 28 | 16% |
Zones are published per ZIP code, so yours is exact even though the metro's is not. The hardiness tool will tell you which one you are in.
Your freeze dates
No freeze range is shown for San Francisco-Oakland-Fremont, CA, because at least one station here records no freeze at any probability, so there is no date to average. The tools below still answer for individual ZIP codes here, and will say what applies.
Your growing season
NOAA publishes a growing-season length for each station, and across the 31 stations serving San Francisco-Oakland-Fremont, CA it runs 197–365 days . That figure is published, not computed from the two freeze dates — subtracting one from the other gives the wrong answer wherever a season crosses New Year. Mean summer high (June–August) runs 62–91 °F , at or above the 90 °F point where cool-season crops bolt and tomato and pepper pollen fails — so midsummer sowings of lettuce and its relatives are worth holding here.
What survives the winter changes across San Francisco-Oakland-Fremont, CA
Of 74 perennial fruits, nuts, berries, vegetables and herbs, 40 come through the winter in zone 9b and only 24 in zone 10b. That is a different garden at each end of the same metro.
| Zone | ZIPs | Survive | Fail for being too warm |
|---|---|---|---|
| 9b | 72 | 40 of 74 | 32 |
| 10a | 79 | 25 of 74 | 49 |
| 10b | 28 | 24 of 74 | 50 |
The last column is the counterintuitive one, and it is why the totals do not simply rise as the winters get milder. Most temperate fruit needs a documented number of hours below about 45 °F to break dormancy and set a crop, so an apple fails in a winter that is too warm; currants and rhubarb cook in the summer heat that comes with it. See the full list with reasons.
The 31 stations behind these numbers
Every figure above comes from these, and each is named so you can check it. Distances vary by ZIP code, so the tools report yours rather than this page guessing.
| Station | NOAA ID | Last spring freeze | First fall freeze | Season |
|---|---|---|---|---|
| Antioch Pumping Plt #3, CA | USC00040232 | January 12 | December 19 | 343 days |
| Berkeley, CA | USC00040693 | January 3 | January 1 | 365 days |
| Bodega 6 Wsw, CA | USW00093245 | January 1 | December 31 | 365 days |
| Concord Buchanan FLD, CA | USW00023254 | January 9 | December 14 | 343 days |
| Concord WWTP, CA | USC00041967 | January 7 | December 19 | 346 days |
| Fremont, CA | USC00043244 | January 7 | December 22 | 353 days |
| Half Moon Bay, CA | USC00043714 | February 6 | December 17 | 328 days |
| Hayward Air Terminal, CA | USW00093228 | January 2 | December 25 | 365 days |
| Kentfield, CA | USC00044500 | January 16 | December 18 | 334 days |
| Livermore, CA | USC00044997 | February 15 | December 2 | 292 days |
| Martinez Wtp, CA | USC00045378 | February 28 | November 22 | 266 days |
| Mt Diablo Junction, CA | USC00045915 | March 8 | December 22 | 282 days |
| Mt Hamilton, CA | USC00045933 | May 3 | November 18 | 197 days |
| Newark, CA | USC00046144 | January 1 | December 27 | 365 days |
| Oakland Metro INTL AP, CA | USW00023230 | January 7 | December 23 | 356 days |
| Oakland Museum, CA | USC00046336 | no freeze recorded | no freeze recorded | 365 days |
| Occidental, CA | USC00046370 | January 29 | December 30 | 347 days |
| Pacifica 4 Sse, CA | USC00046599 | January 11 | January 10 | 365 days |
| Palo Alto, CA | USC00046646 | February 1 | December 7 | 310 days |
| Petaluma AP, CA | USC00046826 | February 28 | November 25 | 271 days |
| Redwood City, CA | USC00047339 | January 17 | December 12 | 333 days |
| Richmond, CA | USC00047414 | January 4 | January 2 | 365 days |
| San Francisco Dwtn, CA | USW00023272 | no freeze recorded | no freeze recorded | 365 days |
| San Francisco INTL AP, CA | USW00023234 | December 29 | December 26 | 365 days |
| San Francisco Oceanside, CA | USC00047767 | December 30 | December 25 | 365 days |
| San Gregorio 2 SE, CA | USC00047807 | March 2 | November 25 | 268 days |
| San Rafael Civic Ctr, CA | USC00047880 | January 11 | December 21 | 349 days |
| Skyline Ridge Preserve, CA | USC00048273 | March 21 | December 15 | 275 days |
| Tracy Pumping Plt, CA | USC00049001 | January 19 | December 10 | 330 days |
| Vallejo, CA | USC00049219 | January 17 | December 27 | 346 days |
| Woodside Fire Stn 1, CA | USC00049792 | February 25 | November 25 | 274 days |
These are medians, not averages — NOAA publishes freeze dates as a probability distribution, and half of years freeze later than the date shown.
Work out your own dates
Each of these takes a ZIP code and answers for that ZIP alone, citing the station it used and how far away it is. There is a ZIP box in the header of every page.
- What survives my winter?
Runs on the hardiness zone, so it answers for all of San Francisco-Oakland-Fremont, CA at once — zone across 74 perennial fruits, berries, vegetables and herbs.
- When do I start my seeds?
Dates every spring job from your own last freeze — sow indoors, set out, direct sow.
- When do I sow the next round?
How often each crop is worth re-sowing, and when the next sowing is due.
- What can I still plant?
Counts the growing days left before your first fall freeze, crop by crop.
Where these numbers come from
The hardiness zone is the USDA 2023 Plant Hardiness Zone Map, published per ZIP code by PRISM at Oregon State. The freeze dates are NOAA's 1991–2020 Climate Normals, read from every station whose normals cover a ZIP code in this metro. Nothing here is estimated, and no station stands in for another.
This page names no single station on purpose. Picking one to represent a metro sounds reasonable and is not: the station serving the most ZIP codes is an artifact of where ZIP centroids happen to fall, and it selects a lock on the Monongahela for Pittsburgh and a far southern suburb for Chicago. A range across every station is true; a single cited date for a whole metro is not.