Berries of all varieties are simply a summertime treat in a large part of the United States, but on California's Central Coast you can find fresh, ripe blueberries, blackberries, and raspberries at your local farmers' market.
Chuy Berry Farm of Arroyo Grande sells at markets throughout the area (and Los Angeles County too) seven days a week! The company's "hoop house" growing method is how they do it. The enclosures keep the berries from freezing in the winter and protect them from too much sun in the summer.