The first vineyards in Mendocino were established in the 1850s in the Redwood Valley by returning farmers who failed to find their wealth and prosperity during the California Gold Rush.

Most of these winery operations stayed small and were completely eradicated by the enactment of Prohibition in the United States in the early 20th century.

[2] The oldest continually operating commercial winery in Mendocino County is Parducci Wines founded in 1931 while Prohibition was still in place.

The land to the west of the ranges, closest to the coast tend to have more maritime climate that includes more cooling and rain influences from the Pacific Ocean.

East of the ranges, the climate turns warmer and more Mediterranean around Ukiah and along the path of the Russian River as it makes its way southward to Sonoma County.

At high elevations in Anderson Valley and nearby Mendocino Ridges beyond the fog's reach, these warmer pockets of lands will usually be planted with more warm climate varieties like Zinfandel.

The average annual rainfall of 38 inches (970 mm) is mostly consolidated in the winter months, which means that drought is a common viticultural hazard that often requires supplemental irrigation.

The warm allows this part of the county develop full bodied and very ripe red wines from Cabernet Sauvignon, Merlot, Petite Sirah and Zinfandel.

[2][12][14] The Anderson Valley is one of California's coolest wine growing regions in the state being deeply influenced by the cool Pacific fog coming in off the coast.

[13] The area around the cities of Philo and Navarro, California in the center and north end of the valley receive considerably more cooling fog influence than the plantings closer to Boonville in the south.

The direct exposure to the sun gives these isolated patches of vineyards more warmth which contributes to the spicy, berry notes of the Zinfandels produced in this part of the Anderson Valley.

In the southern reaches of Redwood Valley is the Ricetti bench, a fluvial terrace the features crimson red soil, where Mendocino County's first vineyards were planted in the 1850s.

[2] The Redwood Valley is slightly cooler than the vineyard plantings to the south towards Ukiah, allowing the area to produce wines with more acidity and deeper color.

[5] In the 21st century, Potter Valley has developed a reputation for white grape varieties such as Chardonnay and Sauvignon blanc as well as Pinot noir from its pockets of cooler microclimates.

[2] The climatic and geographical diversity of Mendocino county, allows the region to produce a wide range of grape varieties for wine production.