Deconstruct SunSan Jose, CA: Hardiness Zone 9b & Sunlight by Season
San Jose is in USDA hardiness zone 9b. Here’s what that means for winter, plus sunrise, sunset, daylight hours and the sun’s path through the year.
Zone 9b in San Jose
On the 2023 USDA Plant Hardiness Zone Map, San Jose falls in zone 9b. That means the coldest night of a typical winter drops to between 25 and 30 °F. Perennials, shrubs and trees labeled for zone 9b or colder (a lower number) should survive the winter here.
A zone only covers winter cold. For a plant to do well it also needs the right amount of sun, and that varies far more from one corner of a yard to the next than the zone does across town.
This is not the official USDA Plant Hardiness Zone Map. Zones are derived from the official 2023 dataset, resampled to about 2 km.
Nearby cities
- Sunnyvale, CA Zone 10a
- Fremont, CA Zone 10a
- Santa Cruz, CA Zone 10a
- Hayward, CA Zone 10a
- Oakland, CA Zone 10a
- Salinas, CA Zone 9b
- San Francisco, CA Zone 10b
- Berkeley, CA Zone 10a
The sun over San Jose
On the June solstice the sun rises in the northeast at 5:47 AM and climbs to 76° above the horizon at 1:09 PM. On the December solstice the noon sun reaches only 29°, so a 20-foot tree casts a noon shadow about 36 feet long. In June the same tree’s noon shadow is only 5 feet.
Sunrise, sunset & daylight by month
| Date | Sunrise | Sunset | Daylight | Noon sun |
|---|---|---|---|---|
| Jan 21 | 7:17 AM | 5:19 PM | 10h 02m | 33° |
| Feb 21 | 6:48 AM | 5:53 PM | 11h 05m | 42° |
| Mar 21 | 7:09 AM | 7:20 PM | 12h 11m | 53° |
| Apr 21 | 6:24 AM | 7:48 PM | 13h 24m | 65° |
| May 21 | 5:53 AM | 8:14 PM | 14h 20m | 73° |
| Jun 21 | 5:47 AM | 8:31 PM | 14h 44m | 76° |
| Jul 21 | 6:03 AM | 8:23 PM | 14h 21m | 73° |
| Aug 21 | 6:28 AM | 7:51 PM | 13h 22m | 65° |
| Sep 21 | 6:54 AM | 7:05 PM | 12h 11m | 53° |
| Oct 21 | 7:21 AM | 6:22 PM | 11h 01m | 42° |
| Nov 21 | 6:52 AM | 4:53 PM | 10h 00m | 33° |
| Dec 21 | 7:17 AM | 4:53 PM | 9h 36m | 29° |
Local time (Los Angeles), including daylight saving time. “Noon sun” is the sun’s height above the horizon at solar noon.
Daylight through the year
What “full sun” means in San Jose
Full sun is 6+ hours of direct sun. In San Jose an open spot has 14.7 hours of daylight to work with in June and 9.6 in December, so a bed that clears 6 hours in summer can easily drop to part shade in winter once the low sun slips behind trees and houses.
Measure the sun in your San Jose yard
Daylight is the ceiling. Deconstruct Sun traces the trees and buildings around one exact spot and tells you its real direct-sun hours, today and at every solstice and equinox.
Questions
What hardiness zone is San Jose, CA in?
San Jose, California is in USDA plant hardiness zone 9b on the 2023 map. The average coldest winter night is 25 to 30 °F (−3.9 to −1.1 °C).
How many hours of daylight does San Jose get?
About 14.7 hours on the June solstice (sunrise 5:47 AM, sunset 8:31 PM) and 9.6 hours on the December solstice (sunrise 7:17 AM, sunset 4:53 PM). Around the equinoxes it is close to 12 hours.
How many hours of sun does my San Jose yard get?
Up to the daylight hours above, minus whatever trees, buildings and fences block. In winter, when the sun stays low, that can be most of it. The Deconstruct Sun iPhone app measures the real direct-sun hours for one exact spot by having you trace what is around it.
When is the best time to plant in San Jose?
Zone 9b tells you which perennials survive winter, not planting dates. For timing, use your local average frost dates from your county extension office, and choose plants rated for zone 9b or colder.
Source: USDA Plant Hardiness Zone Map, 2023. Agricultural Research Service, U.S. Department of Agriculture, planthardiness.ars.usda.gov. Underlying data © PRISM Group, Oregon State University, prism.oregonstate.edu, accessed 2026-08-30. Sun times calculated for 37.296, -121.815.