Called the “Little Sonoma County,” the Sonoma Valley area is a patchwork of viticultural areas and diverse geographics. There are mountains, foothills, plains and valleys, all of varying soil types and contrasting climatic conditions.
As the fog which originates in Tomales Bay in the late afternoon, moves in towards the valley, it curves around both sides of Sonoma Mountain, creeping into the Valley of the Moon from both the north and south. Because the fog never meets near Glen Ellen, there is one pocket that has coastal warm climatic conditions. The vineyards on the slopes of Sonoma Mountain which sit above the fog influence are considered coastal warm as well.
In the cooler valley areas, plantings consist of early ripening varieties such as Chardonnay, Pinot Noir, Merlot and some Johannisberg Riesling and Gewürztraminer. The coastal warm areas at higher elevations and in the Glen Ellen Gap, do well with Zinfandel and Cabernet Sauvignon. The Carneros region, in the southeastern part of the valley near the Napa-Sonoma county line, was once considered too cool to ripen most varieties sufficiently. Now, this area is known for having the ideal climatic conditions for Chardonnay and Pinot Noir production.
Courtesy of Sonoma County Wineries Association