California Growing Zones - USDA Zone Map For California

There is no other state quite like California. It stretches most of the way up the West Coast of the country, making up 75 percent of the coastline. It is some 900 miles long and 250 miles wide, with many regions. People tend to divide the state into Northern California and Southern California, but, in fact, its geography is far more complicated. It includes the Inland Empire, the Central Valley, the mountainous regions and the incredible deserts.

When it comes to USDA growing zones, different sections of the huge state have different zones. California hardiness zones range from USDA zone 5 to USDA zone 10. And some areas - like the deserts and the Central Valley - get extremely hot in summer.

But if you are talking about planting zones, you may be surprised to learn that the vast majority of the state of California falls between hardiness zone 8 and hardiness zone 10. Let’s review each of the major regions of the state.

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More About USDA Hardiness Zone Map

This planting zone map is based on the 2023 USDA plant hardiness map, which was adjusted for the warmer temperatures that have occurred over the past few decades.

The reason understanding what the zones for plants and trees are in California is important is because the zones will help you select the very best plants to grow in your garden.

Planting flowers, vegetables, trees and other plants in your garden that are appropriate for your zone will ensure that they will grow well and will survive from one year to the next.

A well run nursery will clearly mark what zone a plant is appropriate for. Any plant that belongs to a planting zone with a lower number than the one you live in will need protection from the cold in the winter.

Northern California: Pacific Coast

Coastal northern California runs from the Oregon border down to San Luis Obispo, and the climate near the Pacific is surprisingly homogenous. All have California growing zones between 8 and 9. Up north, near Eureka and Arcata, the zones are largely between 8 and 9. As you get to San Francisco, the planting zones edge up to 9 or 10. In USDA zone 8, the average minimum winter temperatures range from 10-20 degrees F, in zone 9 they range from 20-30 degrees F, and in zone 10, they range from 30-40 degrees F.

The zones are based on the average lowest temperature in winter, not taking into account the maximum temperatures or any other factors. Coastal areas often have fog from the Pacific cooling summer temperatures and it isn’t always easy to grow vegetables that need all day sun. Still, the area is said to have a Mediterranean climate, with wet, cooler winters and dry, warmer summers.

Northern California: Inland

Away from the Pacific in Northern California, the hardiness zones are surprisingly similar to coastal zones, mostly ranging from USDA zone 8 - 10. Yes, these areas are warmer, significantly warmer than the coastal regions in summer. But the average winter temperatures are largely the same.

For example, I live in San Francisco by the ocean and my best friend lives on the other side of the Bay in Walnut Creek. Even when we are shivering under thick morning fog here in San Francisco, my friend is complaining about the heat in Walnut Creek. But we all have the same average minimum temperatures.

Central Valley

The Central Valley is an inland area including both the San Joaquin Valley and the Sacramento valley. It is the agricultural heartland of California. And, like so many of the coastal regions of the state, the USDA zones in this section generally fall within USDA hardiness zones 8a to 9a.

This area is very hot in the summer, and I decline to drive through it unless I am in a car with air conditioning. But winters - they are the same mild winters as you find on the Pacific Coast.

Southern California: Pacific Coast

What hardiness zone is Southern California? Well, let’s look first at the coastal area. The hardiness zones for the parts of Southern California near the Pacific generally range from 9 to 11. Again, the farther north, the more likely the hardiness zone will be 9-10, but farther south, you can expect 10-11.

The climate here is also considered a mild, Mediterranean climate with warm, dry summers and cooler, wet winters. These zones are ideal for many species of garden plants.

Southern California: Inland Empire

Moving inland from the Southern California Pacific Coast, you find the Inland Empire. The Inland Empire is a metropolitan area east of greater Los Angeles, largely found in the Riverside and San Bernardino counties. We hate to get monotonous, but the range of hardiness zones in this part of California remains USDA hardiness zones 8 to 9.

This region also experiences hot summers and cooler winters. When we say hot, we mean hot! The season of heat lasts three months and the average daily high temperature is 89 degrees F. In August, the average high is 94 degrees F.

Inland Desert Region

California's Inland Deserts are found in Imperial and Inyo counties and include both the Mojave and Sonoran deserts. Much of this area is federally protected land, with National Parks, wildlife refuges and protected ecosystems.

Surely we are going to get some different planting zones in this part of California? Nope. This area has hardiness zones that range from 8-11. But summers bring extreme heat, that is not reflected in the planting zone designation. The deserts have many extremely hot days when the temperature climbs above 95 degrees F. Known as the hottest place on Earth, Death Valley in the Mojave Desert has recorded temperatures of hotter than 125 degrees F in summer.

Sierra Nevada Mountains

California's mountains get colder weather in winter than other regions in the state. generally fall within USDA hardiness zones 5 to 7, They also have shorter growing seasons. There are three mountain ranges in the state, the Sierra Nevada, largely in USDA zones 5-7, the Cascade Range, with a hardiness range of 5-6, and the San Bernardino Mountains, generally in USDA zones 6-8.

How cold are these zones? An area in USDA zone 5 has an average minimum temperature of -20 to -10 degrees F. In zone 6, the average minimum temperature drops to -10 to 0 degrees F, while zone 7 is a bit warmer, with an average minimum temperature of 0 - 10 degrees F.

Plant Outside Your Zone with Season Extenders