Napa is warmer in the summer than Sonoma County, to the west, or Santa Barbara County, a wine-producing county in southern California. Thus, the Napa wineries favor varietals such as Cabernet Sauvignon, while Pinot noir and Chardonnay are more the specialty of Sonoma and Santa Barbara wineries. At the north end of Napa County, in the Mayacamas Mountains, lies Mount Saint Helena, the Bay Area's second tallest peak at 4,344 feet (1,323 m) and home to Robert Louis Stevenson State Park; Snell Valley is also situated in northern Napa County; the Missimer Wildflower Preserve is within Snell Valley. On the west side of the Napa Valley is Hood Mountain, elevation 2,750 feet (838 m).