California
Although 50 American states produce wine, California alone accounts for around 85% of the country's production, making the state the world's 4th-largest producer after Italy, France and Spain. The climate is strongly influenced by the Pacific Ocean, which at this latitude is a cold ocean. Wine regions close to the Pacific have an oceanic climate that becomes Mediterranean the further inland you go, and more continental near the Sierra Nevada. Bays and inlets such as San Pablo Bay act as thermal regulators for viticulture, particularly in the Napa and Sonoma valleys.
The sub-region: Los Carneros
Los Carneros is one of California's oldest and most famous wine regions. It began producing wine in 1830 and today ranks among the world's finest regions for Pinot Noir and Chardonnay. Located north of San Pablo Bay and along the low hills of the Mayacamas range, Los Carneros regularly enjoys fog and cool breezes off the bay. This unique situation results in a cooler, more moderate climate than that of the wine regions further north, in the Napa and Sonoma valleys.