There are two zone maps to consider when planning your Sacramento landscape: the USDA hardiness zone and the Sunset climate zone.
USDA Zone Map
The USDA zone map is based off of winter low temperatures.
As you can see from the map, zone 9 dominates the Sacramento area. Plants recommended for zone 9 should survive our mild winters.
Sunset Zone Map
Sunset zone maps take things a step further and depending on whether your are landscaping in Sacramento itself, or up toward the hills, your zone may be either 14 or 9.
Sunset climate zones take mulitple factors into consideration to ensure that plants don’t simply survive, but thrive!
ZONE 9: Thermal belts of California’s Central Valley
As cited in the description of Zone 8, the biggest readily apparent difference between Zones 8 and 9 is that Zone 9, a thermal belt, is a safer climate for citrus than Zone 8, which contains cold-air basins. The same distinction, thermal belt versus cold-air basin, determines which species and varieties—hibiscus,melaleuca, pittosporum, and other plants—are recommended for Zone 9 but not for Zone 8. Zones 8 and 9 have the following features in common: summer daytime temperatures are high, sunshine is almost constant during the growing season, and growing seasons are long.Deciduous fruits and vegetables of nearly every kind thrive in these long, hot summers; winter cold is just adequate to satisfy the dormancy requirements of the fruit trees. Fiercely cold, piercing north winds blow for several days at a time in winter, but they are more distressing to gardeners than to garden plants.You can minimize them with windbreaks. In both Zones 8 and 9 tule fogs (dense fogs that rise from the ground on cold, clear nights) appear and stay for hours or days during winter. The fogs usually hug the ground at night and rise to 800 to 1,000 feet by afternoon. Heat-loving plants such as oleander and crape myrtle perform at their peak in Zones 8 and 9 (and 14). Plants that like summer coolness and humidity demand some fussing; careful gardeners accommodate them by providing filtered shade from tall trees and plenty of moisture. In Zone 9,winter lows over a 20-year period ranged from 28 to 18°F (–2 to –8°C).
ZONE 14: Northern California’s inland areas with some ocean influence
Marine air moderates parts of Zone 14 that otherwise would be colder in winter and hotter in summer. The opening in Northern California’s Coast Ranges created by San Francisco and San Pablo bays allows marine air to spill much farther inland. The same thing happens, but the penetration is not as deep, in the Salinas Valley. Zone 14 includes the cold-winter valley floors, canyons, and land troughs in the Coast Ranges from Santa Barbara County to Humboldt County.
The milder-winter, marine-influenced areas in Zone 14 and the cold-winter inland valley within Zone 14 differ in humidity. For example, lowland parts of Contra Coasta County are more humid than Sacramento.
Fruits that need winter chill do well here, as do shrubs needing summer heat (oleander, gardenia). Over a 20-year period, this area had lows ranging from 26 to 16º F (–3 to –9ºC). Weather records show all-time lows from 20 down to 11ºF (–7 to –12º C).
