The U.S. State of California is very geologically diverse region and is equally varied in the range of climates and terroirs that can be found. Most of the state's wine regions are found between the Pacific coast and the Central Valley. The Pacific Ocean and large bays, like San Francisco Bay serve as tempering influences to the wine regions nearby providing cool winds and fog that balance the heat and sunshine. While drought can be a viticultural hazard, most areas of California receive sufficient amounts of rainfall with the annual rainfall of wine regions north of San Francisco between 24-45 inches (615–1150 mm) and the more southern regions receiving 13-20 inches. Winters are mild with little threat of frost damage though springtime frost can be a hazard. To curb the threat of frost, vineyard owners will often employ the use of wind machines, sprinklers and smudge pots to protect the vines.
While California's wine regions can be generally classified as having a Mediterranean climate, there are also regions with more continental climates. Proximity to the Pacific or bays as well as unobstructed access to the cool currents that come off them will dictate the relative coolness of the wine region. Areas surrounded by mountain barriers, like some parts of Sonoma and Napa counties will be warmer due to the lack of this cooling influence. The soil types and landforms of California vary greatly, having been influenced by the plate tectonics of the North American and Pacific Plates. In some areas the soils can be so diverse that vineyards will establish blocks of the same vine variety planted on different soils for purpose of identifying different blending components. This diversity is one of the reasons why California has so many different and distinct American Viticultural Areas.
Wine producing areas[]
Central Coast and Santa Cruz Mountains
- Central Coast AVA
- Arroyo Grande Valley AVA
- Arroyo Seco AVA
- Carmel Valley AVA
- Chalone AVA
- Cienega Valley AVA
- Edna Valley AVA
- Hames Valley AVA
- Lime Kiln Valley AVA
- Livermore Valley AVA
- Monterey AVA
- Mt. Harlan AVA
- Pacheco Pass AVA
- Paicines AVA
- Paso Robles AVA
- San Antonio Valley AVA
- San Benito AVA
- San Bernabe AVA
- San Francisco Bay AVA
- San Lucas AVA
- San Ysidro District AVA
- Santa Clara Valley AVA
- Santa Lucia Highlands AVA
- Santa Maria Valley AVA
- Santa Ynez Valley AVA
- Sta. Rita Hills AVA
- York Mountain AVA
- Central Valley (not an AVA as such)
- Alta Mesa AVA
- Borden Ranch AVA
- Capay Valley AVA
- Clarksburg AVA
- Clements Hills AVA
- Cosumnes River AVA
- Diablo Grande AVA
- Dunnigan Hills AVA
- Jahant AVA
- Lodi AVA
- Madera AVA
- Merritt Island AVA
- Mokelumne River AVA
- River Junction AVA
- Salado Creek AVA
- Sloughhouse AVA
- Tracy Hills AVA
- Klamath Mountains (not an AVA as such)
- Seiad Valley AVA
- Trinity Lakes AVA
- Willow Creek AVA
- North Coast AVA
- Alexander Valley AVA
- Anderson Valley AVA
- Atlas Peak AVA
- Bennett Valley AVA
- Benmore Valley AVA
- Calistoga AVA
- Chalk Hill AVA
- Chiles Valley AVA
- Clear Lake AVA
- Cole Ranch AVA
- Covelo AVA
- Diamond Mountain District AVA
- Dos Rios AVA
- Dry Creek Valley AVA
- Green Valley of Russian River Valley AVA
- Guenoc Valley AVA
- High Valley AVA
- Howell Mountain AVA
- Knights Valley AVA
- Los Carneros AVA
- McDowell Valley AVA
- Mendocino AVA
- Mendocino Ridge AVA
- Mt. Veeder AVA
- Napa Valley AVA
- North Coast AVA
- Northern Sonoma AVA
- Oak Knoll District of Napa Valley AVA
- Oakville AVA
- Potter Valley AVA
- Red Hills Lake County AVA
- Redwood Valley AVA
- Rockpile AVA
- Russian River Valley AVA
- Rutherford AVA
- Solano County Green Valley AVA
- Sonoma Coast AVA
- Sonoma Mountain AVA
- Sonoma Valley AVA
- Spring Mountain District AVA
- St. Helena AVA
- Stags Leap District AVA
- Suisun Valley AVA
- Wild Horse Valley AVA
- Yorkville Highlands AVA
- Yountville AVA
- Sierra Foothills AVA
- California Shenandoah Valley AVA
- El Dorado AVA
- Fair Play AVA
- Fiddletown AVA
- North Yuba AVA
- Sierra Foothills AVA
- South Coast AVA
- Cucamonga Valley AVA
- Leona Valley AVA
- Malibu-Newton Canyon AVA
- Ramona Valley AVA
- Saddle Rock-Malibu AVA
- San Pasqual Valley AVA
- South Coast AVA
- Temecula Valley AVA