Napa Valley consists of 15 sub appellations (AVA’s)

Atlas Peak
– Climate: Lying just about the fog line, this mountainous region has a cool climate with temperatures 10 to 15°F cooler than the Valley floor in summer, when it rarely reaches above 90°F.
– Elevation: 760 to 2,600 feet.
– Soils: Volcanic with basaltic red color, shallow with limited water retention.
– Known for Cabernet Sauvignons with berry and cherry fruitiness, and more acidity than wines from Stags Leap District. Chardonnays from the area are crisp and floral with distinctive pear flavors. The rainfall averages about 38 in annually.

– Climate is warm to hot, and depending upon time of year; lower humidity. Top summer temperatures are 90°F and drop to low 50s°F, Marine air flowing from the NW brings cool afternoons and evening breezes.
– Elevation: 300 to 1200 ft,  Rainfall: 38 to 60 in annually
– Soil: Almost all of the soil is of volcanic origin and ranges from rocky along the hills, to more cobble-like loam throughout the alluvial fans. The valley centers have a heavier, more clay soil.
– Known for Cabernet Sauvignons, Zinfandel, Syrah and Petite Syrah, and Zinfandel

(Los) Carneros
– Climate: Cool and breezy (winds from San Pablo Bay and through Petaluma Gap to the West) makes it well suited for Chardonnay’s and Pinot Noirs. Highs in the summer around 80°F.
– Elevation: 15 to 400 ft,  Rainfall is the lowest in Napa Valley 18 to 24 in annually
– Soil: generally shallow and clay based
– Known for pear and spice Chardonnays, earthy and spiced Pinot Noirs, and strong Merlots with herbal undertones. Syrah and Merlot can also perform very well in certain areas of Carneros.

Chiles Valley District
– Climate: Warm summer days typically in the high 80s°F, however high elevation and foggy summer nights create rather cool evenings below 50°F. Cold winters and springs can be accompanied with strong winds.
– Elevation: 800 to 1,300 ft,  Rainfall: 35 in annually
– Soil:  The valley floor offers silty-clay soil with marine origin and good fertility. The hillsides offer more clay and stone loam that is less fertile.
– Known for Cabernet Sauvignons and Merlots with good acidity. The Cabs often have fruity flavors and the Merlots typically have bold cherry flavor with a hint of cocoa.

Diamond Mountain District
– Climate:  Influenced by ocean breezes and fog which results in large temperature swings between day and night helps to preserve the acidity of the grapes. There are lower maximum temperatures and higher minimums due to altitude. Ranges from 50 to 95°F during growing season.
– Elevation: 400 to 2,200 ft,  Rainfall: 40 to 55 in annually – One of the northernmost sub regions
– Soil:  Steep and rocky terrain, soil is mainly volcanic or sedimentary and often gritty with a reddish hinge
– Region known for full-bodied and structured Cabernets with strong flavors. Area can also be good for fruity and full-bodied Chardonnays.

Howell Mountain
– Climate: is warm and dry because of a strong afternoon sun. There are also cool nights which help maintain acidity.
– Elevation: 600 to 2200 ft,  Rainfall: 40 to 50 in annually
– Soil: Typically the soils of the region are volcanic based, and shallow with low fertility and high drainage
– First sub region to gain AVA in 1984
– Region begins at elevation of 1,400 feet, above the fog belt, meaning warmer mornings and cool breezes in the afternoon
– Known for Cabernets and Zinfandels (Cabernets – dense, rich with earthy undertones – Zinfandels – intense and bold)

Mt. Veeder
– Climate: District has 2 different climates, one cooler than the other. This caused problems in the early days of the AVA because the cool side was not warm enough for the Cabernet grapes to fully ripen – this resulted in some of the Cabernets gaining a reputation for having green tannins. The problem has been solved by planting Cabernets in the warmer areas, and Syrah and Merlot in the cooler areas. Most vineyards are now located above the fog belt giving way to a more moderate climate with warmer nights and cooler days. Average summer high is 85°F.
– Elevation: 600 to 2,100 ft,  Rainfall: 35 in annually
– Soil: Most of soil is sandy, sedimentary based, shallow and well-drained. It also has more acid and lower fertility.
– Mt. Veeder is known for dense, rich and earthy Cabernet Sauvignon.

Oak Knoll District
– Climate: Moderate to cool temperament; marine air and fog can linger until late morning. There are typically early evening breezes with slightly cooler temperatures than other regions. Summer high temperatures low 90s°F with low 50s°F at night. The cooler climate leads to a smaller crop size than other AVAs and slightly longer growing seasons.
– Elevation: sea level to 800 ft, Rainfall: 36 in annually
– The main feature of Oak Knoll is Napa Valley’s largest alluvial fan formed by Dry Creek.
– Soil: The NW of the region has mainly volcanic soils with stony or gravelly texture. The S and E areas are a mix of gravel to a silty, clay loam.
– Region is known for Merlots, Chardonnays and Cabernet Sauvignons.

– Climate: Moderately warm with summer highs of 90s°F. Fog in both morning and evening helps keep the acidity levels to a preferred range. E side of region has warmer afternoon sun.
– Elevation: 75 to 500 ft, Rainfall: 35 in annually
– Soil: is mainly sedimentary or gravelly on the West with heavier, more volcanic soil on the east. The fertility is low to moderate with average water retention.
– Mostly known for Cabernet Sauvignons and Merlots with textured and full, rich fruit flavor. Sauvignon Blanc’s of the area have a steel and fleshy taste.

– Climate: Moderate with influences of morning fog. The west side is cooler with less afternoon sun and some marine winds. Typically summer high temperature is around 95°F.
– Elevation: 100 to 500 ft, Rainfall: 38 in annually
– Soil: Sedimentary, gravelly or sandy with moderate fertility and good water retention; eastern side is more volcanic and more fertile.
– Mainly Cabernet Sauvignon, Merlot and Zinfandel are produced in this AVA – flavors indicative of the region are subtle, yet rich cherry and earthy aromas.

Spring Mountain District
– Climate:  This district has a mild climate with more cool weather. The high elevation and cool nights help maintain acidity.
– Elevation: 600 to 2200 ft, Rainfall: 40 to 50 in annually
– Soil:  Mostly sedimentary, sandstone with high drainage and low fertility.
– Grapes have grown in this region since the 1870’s, but within the last decade a reputation has emerged for rich, bold, dense and dark Cabernet Sauvignon. Rieslings can also be a surprise find here.  Other wines produced here are Merlots and Zins

St. Helena
– Climate:  Has one of the hottest temperatures of Napa’s AVAs; warm due to protection from western hills with less fog and wind. Average summer high of 95°F+
– Elevation: 150 to 600 ft,  Rainfall: 38 to 40 in annually
– Soil:  South and West borders of the region have more sedimentary, gravel-clay soils with average water retention and moderate fertility. In the North and East, soil is more volcanic and fertile.
– Still seeking a regional identity, Cabernet Sauvignon is emerging as an important grape, with deep, rich and fruity aromas.

Stags Leap District
– Climate:  Highly influenced by cool breezes that wind their way through the uneven terrain. Summer high temps are around 100°F.
– Elevation: 66 to 400 ft, Rainfall: 30 in annually
– Soil: Mainly sedimentary and gravelly, and sometimes hard clay bedrock, results in low to moderate fertility. Terrain varies, some small hills/mounds and some large hills with sharp cliffs.
– With unusually long growing season, Cabernets from Stags Leap have a distinctive flavor, full-bodied and velvety; region also known for Merlot and Sangiovese, and fruity and citrusy Sauvignon Blanc.

Wild Horse Valley
– Climate: Warmer region to the east, with prevailing winds from the Suisan Bay to the SE
– Elevation: 400 to 1,500 ft, Rainfall: 35 in annually
– Soil: Typically more volcanic with a distinct red color; also shallow with lower water retention
– Common to the area are Cabernet Sauvignon and Sangiovese with bold fruit flavors, and more acidity than other wines of Napa. Chardonnays are also crisp and pear flavored.

– Climate: Moderate temperament with cool marine breeze and fog which influence cool mornings and comfortable afternoons. Summer temperature may go as high as 90°F and dropping to the mid 50s°F
– Elevation: 20 to 200 ft, Rainfall: 32 in annually
– Soils: Mainly sedimentary based with gravelly and silty texture, average fertility.
– First grapes in Napa Valley planted in Yountville in 1836, was not an official AVA until 1999
– Best known for Cabernets and Merlots, however this region produces a wide range of wines including Zinfandels and Chardonnays. Region likes subtle yet rich flavors.