Deconstruct SunSunnyvale, CA: Hardiness Zone 10a & Sunlight by Season
Sunnyvale is in USDA hardiness zone 10a. Here’s what that means for winter, plus sunrise, sunset, daylight hours and the sun’s path through the year.
Zone 10a in Sunnyvale
On the 2023 USDA Plant Hardiness Zone Map, Sunnyvale falls in zone 10a. That means the coldest night of a typical winter drops to between 30 and 35 °F. Perennials, shrubs and trees labeled for zone 10a or colder (a lower number) should survive the winter here. Parts of the area sit near the boundary with zone 9b, so a sheltered courtyard or an exposed hilltop can behave like the neighboring zone.
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
- Fremont, CA Zone 10a
- San Jose, CA Zone 9b
- Hayward, CA Zone 10a
- Santa Cruz, CA Zone 10a
- Oakland, CA Zone 10a
- San Francisco, CA Zone 10b
- Berkeley, CA Zone 10a
- Salinas, CA Zone 9b
The sun over Sunnyvale
On the June solstice the sun rises in the northeast at 5:47 AM and climbs to 76° above the horizon at 1:10 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 | 7:18 AM | 5:20 PM | 10h 02m | 33° |
| Feb 21 | 6:49 AM | 5:54 PM | 11h 05m | 42° |
| Mar 21 | 7:09 AM | 7:21 PM | 12h 11m | 53° |
| Apr 21 | 6:25 AM | 7:49 PM | 13h 24m | 65° |
| May 21 | 5:54 AM | 8:15 PM | 14h 21m | 73° |
| Jun 21 | 5:47 AM | 8:32 PM | 14h 45m | 76° |
| Jul 21 | 6:03 AM | 8:24 PM | 14h 21m | 73° |
| Aug 21 | 6:29 AM | 7:52 PM | 13h 23m | 64° |
| Sep 21 | 6:55 AM | 7:06 PM | 12h 11m | 53° |
| Oct 21 | 7:22 AM | 6:22 PM | 11h 01m | 42° |
| Nov 21 | 6:53 AM | 4:53 PM | 10h 00m | 33° |
| Dec 21 | 7:18 AM | 4:53 PM | 9h 35m | 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 Sunnyvale
Full sun is 6+ hours of direct sun. In Sunnyvale an open spot has 14.8 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 Sunnyvale 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 Sunnyvale, CA in?
Sunnyvale, California is in USDA plant hardiness zone 10a on the 2023 map. The average coldest winter night is 30 to 35 °F (−1.1 to 1.7 °C). It is near the boundary with zone 9b.
How many hours of daylight does Sunnyvale get?
About 14.8 hours on the June solstice (sunrise 5:47 AM, sunset 8:32 PM) and 9.6 hours on the December solstice (sunrise 7:18 AM, sunset 4:53 PM). Around the equinoxes it is close to 12 hours.
How many hours of sun does my Sunnyvale 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 Sunnyvale?
Zone 10a 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 10a 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 37.386, -122.026.