California
If 50 American states produce wine, Californian production alone represents approximately 85% of the country's production, making this state the 4th largest producer in the world behind Italy, France and Spain. The climate is strongly influenced by the Pacific Ocean which at this latitude is a cold ocean. The wine-growing regions located near the Pacific have an oceanic climate becoming Mediterranean the further inland you go from the ocean and it becomes more continental near the Sierra Nevada. Bays and openings to the sea, such as San Pablo Bay, act as thermal regulators on viticulture, particularly in Napa and Sonoma Valley.
The sub-region: Napa Valley
Napa Valley, located an hour's drive north of San Francisco, is the most famous and prestigious wine region in the New World. Although a number of grape varieties are grown in the valley's vineyards, the region is particularly known for its Cabernet Sauvignon. Climate, geology and topography are three essential components that make Napa Valley a premier wine region. The combined influences of San Pablo Bay and the hills of the North Coast Ranges are responsible for the valley's very unique microclimate. The bay generates morning fog and the hills channel it inland into the valley. Without this fog that comes from the bays, the climate in the valley would be significantly warmer than it is, making it difficult to achieve structure and balance in the wines.
