The vineyards of Southern California comprise those within the following counties:- [Los Angeles](/county/los-angeles-county), [San Diego](/county/san-diego-county), [Riverside](/county/riverside-county) and [San Bernardino](/county/san-bernadino-county). The hot, dry climate at this latitude dictates that most of the viticultural areas are confined to coastal regions where the high temperatures are tempered by the cool Pacific Ocean breeze, or elevated plots inland, where the high altitude has the same moderating effect. Indeed, Southern California is home to the state’s highest vineyard - at an altitude of two-thousand-and-fifty-seven metres above sea level, Stone Summit, in Big Bear Lake ([San Bernardino County](/county/san-bernadino-county)) claims to be the highest in the entire northern hemisphere. Although today, the AVAs of the Southern counties play a largely supporting role to the superstar leads of [Napa](/county/napa-county) and [Sonoma](/county/sonoma-county), this region is often cited as the birthplace of [Californian](/region/california) wine, and prior to Prohibition was amongst the state's most productive viticultural areas. Urban Sprawl, particularly the growth of cities such as Los Angeles and San Diego, together with the destruction caused by Pierce’s disease in the late twentieth century, had led to the region being largely forgotten about until fairly recently. However, with a renewed verve and a focus on delivering elegant, terroir driven wines from a broad range of grapes, the area is re-establishing itself as a serious winemaking sub-zone. The key red grapes of the region are [Zinfandel](/zinfandel), the [Bordeaux](/region/bordeaux) varieties [Cabernet Sauvignon](/cabernet-sauvignon), [Cabernet Franc](/cabernet-franc) and [Merlot](/merlot), and types typical of the [Rhône Valley](/region/rhone-valley) such as [Grenache](/grenache) and [Syrah](/syrah). [Sangiovese](/sangiovese) and [Tempranillo](/tempranillo) are also gaining a reputation for success in some of the area’s AVAs - notably [Temecula Valley](/ava/temecula-valley-ava) and [Antelope Valley of the California High Desert](/ava/antelope-valley-of-the-california-high-desert-ava), whilst [Chardonnay](/chardonnay), [Sauvignon Blanc](/sauvignon-blanc) and to a lesser degree [Viognier](/viognier), are the most prevalent whites.