Appellations (AVAs)

The Appellations Of California Wine – North Coast
The North Coast American Viticultural Area (AVA) in California, covering more than three million acres, includes Napa, Sonoma, Mendocino and Lake counties, and portions of Marin and Solano counties. The area forms a slightly crooked rectangle, approximately 100 miles long and more than 50 miles wide. A winemaking mecca since the mid 19th century, today the area features about 800 wineries, nearly half of the total wineries in the state. American Viticultural Areas are to appellations of origin as grapes are to fruit. AVAs are delimited grape-growing areas distinguishable by geographic, climatic and historic features, and the boundaries have been delineated in a petition filed and accepted by the federal government. In size, AVAs range from extremely small to extremely large. AVAs are one kind of appellation, but not all appellations are AVAs. An appellation can also be a political designation, such as the name of a country, the name of a state or states, the name of a county or counties within a state. More information on AVAs and appellations can be found at the Wine Institute’s AVA section.

Sonoma-AVA-MapSonoma County Appellations (data as of May 2014)
Sonoma County has more than 400 wineries, almost 60,000 acres of vineyards, and an amazing range of terroir and microclimates.  This distinguishes Sonoma County, one of the most diverse and special winegrowing regions in the world.  Sonoma County, California, stretches from the Pacific Coast in the west to the Mayacamas Mountains in the east. Within the borders are 16 American Viticultural Areas (AVAs, or appellations) – each with its own distinctive characteristics.

Alexander Valley
15,000 vineyard acres / 42 wineries / Earned AVA status in 1984
Almost as warm as Knights Valley, the valley floor of Alexander Valley has gravelly soil that produces some of the county’s richest Cabernet Sauvignon, along with flavorful, ripe Chardonnay. The Valley’s hillsides produce complex and concentrated Zinfandel, Merlot, and Cabernet Sauvignon.

Bennett Valley
650 vineyard acres / 4 wineries / Earned AVA status in 2003
Merlot shines in Bennett Valley like nowhere else, with volcanic-laced, clayey soils and a moderately cool climate that results in extended hang time ideal for the varietal. The long growing season helps maximize flavors and increase concentration, while the cooler temperatures preserve the grape’s natural acidity.

8,000 vineyard acres / 22 wineries / Earned AVA status in 1983
One of the world’s premier winegrowing regions, Los Carneros – “The Ram” in Spanish – is located less than 40 minutes from San Francisco, Marin County, the East and North Bays. Sacramento and the South Bay are both just a short distance further. A cool climate appellation, Carneros has long been known for its unassailable Chardonnays, elegant Pinot Noirs and its sparkling wines. In recent years, Carneros has been recognized for the quality of its Syrah, its Merlot and new varietals now emerging throughout the appellation.

As inland temperatures rise during the day, moist air over the cold Pacific is drawn inland over Carneros, cooling temperatures from mid afternoon into evening. These fresh afternoon winds slow activity in leaves, stressing the vines even when irrigated. Fog rolls in throughout the night and this provides a gentle buffer to the next morning’s sun, repeating the climatic cycle. Carneros was the first wine region based on climate rather than political boundaries. It received its designation in 1983.

Carneros soils tend to be dense, shallow (approximately three feet deep), high in clay content, and of low to moderate fertility. These soils impact the vine’s vigor by restricting development of the root system, providing just enough nutrients and water to sustain growth without excess development. Subsoils also vary in Carneros. Each of the different subsoils substantially changes the environment of a grapevine’s roots, and affect the composition of the fruit. Thus it is no surprise to find diversity in Carneros wines.

Chalk Hill
1,400 vineyard acres / 4 wineries / Earned AVA status in 1983 w/revision in 1988
Soil, climate and elevation all separate Chalk Hill from other parts of Sonoma’s
Russian River Valley. Occupying the northeast corner of the larger Russian River AVA, Chalk Hill is named for its unique, volcanically-derived, chalky white ash soils. These mildly fertile soils lend themselves to the production of excellent whites, particularly Chardonnay and Sauvignon Blanc. Chalk Hill’s five wineries sit above the rest of the valley, on the western benchland slopes of the Mayacamas Mountains, separating Sonoma from Napa. The appellation enjoys a warmer climate relative to the rest of the Russian River Valley. Due to the higher elevation of this viticultural area, vineyards escape much of the cooling fog that regularly shrouds the lower-lying growing areas near the river.

Dry Creek Valley
10,000 vineyard acres / 50 wineries / Earned AVA status in 1983
Approximately 16 miles long and 2 miles wide, Dry Creek Valley is one of the smallest enclosed American Viticultural Areas. Roughly 9,300 acres of vineyards extend along the valley floor, the surrounding benchlands and hillsides, and 58 wineries produce a diverse selection of wines ranging from the renowned Zinfandels to Bordeaux and Mediterranean varietals. The history of grape growing and winemaking in Dry Creek Valley is among the longest in California, with its roots beginning more than 130 years ago.

Morning fog from the Pacific Ocean tempers warm days – good balance of maritime and inland climates. The stone-strewn soils are ideal for concentrating fruit and flavor character of Zinfandel, the hallmark of Dry Creek Valley, along with Cabernet Sauvignon, and the resulting wines are rock solid examples of their types.

Fort Ross – Seaview
506 acres / Established AVA in 2012
Fort Ross-Seaview American viticultural area is located in the western part of Sonoma County, California contains 18 commercial vineyards, lies close to the Pacific Ocean and is about 65 miles north-northwest of San Francisco. It lies entirely within the Sonoma Coast viticultural area and does not overlap, or otherwise affect, any other viticultural areas.

Vineyards within this area are generally located on rounded ridges with summits extending above 1,200 feet consisting of steep, mountainous terrain made up of canyons, narrow valleys, ridges, and 800- to 1,800-foot peaks. Areas above 900 feet in elevation, the climate is influenced by longer periods of sunlight and is warmer than that in the surrounding land below.

Green Valley
3,600 vineyard acres / 10 wineries / Earned AVA status in 1983
Green Valley is one of the smallest appellations in Sonoma County. It lies in the southwestern part of the Russian River Valley, bounded by the towns of Sebastopol, Forestville and Occidental. It is very tightly delineated, both geographically and climatically, and is the most consistent of any North Coast appellation in terms of soil, climate and flavor.

The fog is Green Valley’s trademark. The predominant soil type (60%) of this American Viticultural Area (AVA) is Goldridge soil, the most sought-after type in Sonoma County—especially for Pinot Noir.

Knights Valley
2,000 vineyard acres / 2 wineries / AVA status in 1983
Knights Valley, the most remote of Sonoma County’s appellations, snuggles up against Mt. St. Helena, the area’s most influential feature. The unique character of this appellation can be discovered in its mountain vineyards, where ideal growing conditions have resulted in cabernet sauvignon of regal quality.

Moon Mountain
1,500 vineyard acres / Earned AVA status in 2013
The new “Moon Mountain District of Sonoma County” lies east of Highway 12 and spans 17,663 acres, which includes 1,500 acres of commercial vineyards planted at elevations from 400 to 2,200 feet. The new appellation is located within the Sonoma Valley AVA, but the Moon Mountain vintners and growers have long wanted to distinguish their high elevation wines on the labels.

Northern Sonoma
329,000 acres / AVA established in 1990
The area seems as vast and amorphous as its name, encompassing Chalk Hill, Knights Valley, Alexander Valley, Dry Creek Valley, Russian River Valley, and most of Green Valley within its embrace. The border follows Bohemian Highway in Monte Rio southeast along Dutch Bill Creek through Camp Meeker, Occidental, and Freestone, stretches along Highway 12 through Sebastopol to Fulton Road, turns north to River Road and from there traverses Mark West Springs Road to the Sonoma–Napa border. Its north boundaries are formed by the county lines of Lake and Mendocino.

Pine Mountain – Cloverdale Peak
230 vineyard acres / AVA status in 2011
The viticultural area is totally within the multicounty North Coast viticultural area and overlaps the northernmost portions of the Alexander Valley viticultural area and the Northern Sonoma viticultural area. The area currently has 230 acres of commercial vineyards, with another 150 acres under development. The distinguishing features of the viticultural area include its mountainous soils, steep topography with high elevations, and a growing season climate that contrasts with the climate of the Alexander Valley floor below. Also, the vineyards within the viticultural area generally are small (5-20 acre plots of flat or gently sloping ground).

150 vineyard acres (out of 16,000 in the AVA!) / Became an AVA in 2002
Spreading west of Lake Sonoma to the Mendocino County border, Rockpile is known for intensely-flavored red grape varietals with great concentration and balance. At elevations up to 1,900 feet, Rockpile is too far upland for the penetrating fogs that influence other Sonoma appellations. This exposes grapes to more California warmth and sunshine, boosting their ripeness and richness. The appellation is designated by altitude and geography.

Russian River Valley
15,000 vineyard acres / 70 wineries / Earned AVA status in 1983
The Russian River Valley climate is sculpted by the regular intrusion of cooling fog from the Pacific Ocean a few miles to the west. Much like the tide, it ebbs and flows through the Petaluma Wind Gap and the channel cut by the Russian River through the coastal hills. The fog usually arrives in the evening, often dropping the temperature 35 to 40 degrees from its daytime high, and retreats to the ocean the following morning. This natural air-conditioning allows the grapes to develop full flavor maturity over an extended growing season – often 15 to 20 percent longer than neighboring areas, while retaining their all-important natural acidity.

Sonoma Coast
2,000 vineyard acres / 7 wineries (Excluding wineries in Russian River, Green Valley, Carneros, and Chalk Hill) / Earned AVA status in 1987
The Sonoma Coast AVA extends from San Pablo Bay to the border with Mendocino County. The appellation is known for its cool climate and high rainfall relative to other parts of Sonoma County. Close to the Pacific, with more than twice the annual rainfall of its inland neighbors, it can still be warm enough to ripen wine grapes because most vineyards are above the fog line. Pinot Noir and Chardonnay shine, along with cool-climate Syrah.

Sonoma Mountain
800 vineyard acres / 3 wineries / Obtained AVA status in 1985
The 2,400-foot Sonoma Mountain range begins to rise above the town of Glen Ellen at the western edge of the Valley of the Moon. Found here are high-altitude, steep-sloped vineyards, with eastern exposures to catch the fog-free morning sun. These vineyards fall within the larger Sonoma Valley AVA. However, due to the unique hillside terroir, they are entitled to use the more specific designation of the Sonoma Mountain AVA. Powerful, yet elegant Cabernet Sauvignons – the appellation’s specialty – grow here on well-drained soils. The irregular folds and crevices of the mountain slopes also create microclimates suitable for limited production of a diverse range of other varieties, including Chardonnay, Sauvignon Blanc, Semillon, as well as Pinot Noir and Zinfandel.

Sonoma Valley
14,000 vineyard acres / 55 wineries / Earned AVA status in 1981 (amended in ’85 & ’87)
The Sonoma Valley AVA centers on the Sonoma Valley (also known as The Valley of the Moon) in the southern portion of the county. The appellation is bordered by two mountain ranges: the Mayacamas Mountains to the east and the Sonoma Mountains to the west.

Along with being the area where so much of Sonoma County’s winemaking history took place, the area is known for its unique terroir, with Sonoma Mountain protecting the area from the wet and cool influence of the nearby Pacific Ocean. The Sonoma Mountains to the west help protect the valley from excessive rainfall. The cool air that does affect the region comes northward from the Los Carneros region and southward from the Santa Rosa Plain.

Because the valley is cooled from the north and south, it is different from other California north-south-oriented grape growing valleys in the interior.  In addition, the daily wind that makes its way into the northern and southern sections of the valley slows ripening, which prolongs hang time and promotes natural balance in the wines. In the appellations of the North Coast, the wind is unique to Sonoma Valley and Carneros.

The soils of the Sonoma Valley, like the rest of the county are varied. One finds a wide disparity between valley floor and mountain soils; those found in flatter, valley areas tend to be quite fertile, loamy and have better water-retention while the soils at higher elevations are meager, rocky and well-drained. In general, the structure, rather than the composition of the soil, is the deciding factor where grape plantings are concerned.

Napa Valley AVA MapNapa Valley Wine Appellations (data as of June 2014)
During the early decades of winemaking in the Napa Valley, grapes were often planted in patchwork pattern vineyards in which many varieties were mixed. But experience has since shown the wisdom of matching grapes with locations whose microclimates and soils are best suited to particular grape varieties. Within the Napa Valley, regions have emerged that possess distinct microclimates and terrains, imprinting recognizable characteristics on the grapes grown within them. Vintners and growers within these regions delineate the boundaries of these growing areas, giving them names that reflect their regional designations, or appellations. The Napa Valley is itself an appellation, and it has been since it received its own AVA designation in 1981. It is California’s first recognized AVA and the second in the United States. Within the Napa Valley appellation exists 15 sub-appellations, including: Atlas Peak, Calistoga, Chiles Valley District, Diamond Mountain District, Howell Mountain, Los Carneros, Mt. Veeder, Oak Knoll District of Napa Valley, Oakville, Rutherford, St. Helena, Spring Mountain District, Stags Leap District, Yountville and Wild Horse Valley.

Atlas Peak AVA
Climate: Cool, mountain-influenced, with temperatures about 10 to 15°F cooler than the Valley floor in summer. Above the fog line, there is a low diurnal change, with summer temperatures rarely above 90°F (32.2°C). Elevation: 760 to 2600 ft (231m to 792m). Rainfall: 38 inches (96cm) annually. Soils: Volcanic in origin, with basaltic red color, shallow with limited water retention, so irrigation is often essential. Principal varieties & characteristics: Cabernet Sauvignon: Bright berry and cherry fruit, and more acidity than wines from Stags Leap District. Chardonnay: Crisp, floral, aromatic, with distinctive pear-mineral flavors and bright acidity.

Calistoga AVA
Climate: Warm to hot, depending upon time of year; lower humidity; summer temperatures peak to 90°F (32.2°C) and fall to low 50s°F (11°C), the result of marine air from the northwest; cool afternoon and evening breezes. Elevation: 300 to 1200 ft (92 to 370m). Rainfall: 38 to 60 inches (96.5 to 150cm) annually. Soils: Almost completely of volcanic origin, soils range from rocky, stony loam on the hillsides, to gravelly or cobbly loams on the alluvial fans, to heavier clay-silt soils in the valley center areas. Principal varieties: Cabernet Sauvignon, Zinfandel, Syrah, Petite Sirah

Chiles Valley District AVA
Climate: Fairly warmer summer days (mid-80°F plus/28.8 to 31°C), but due to higher elevation and summer fog at night, quite chilly at night (below 50°F/10°C). With colder winters and spring, as well as strong winds, harvest comes later than on valley floor at Oakville. Elevation: 800 to 1300 ft. (242 to 394m). Rainfall: 35 inches (88cm) annually. Soils: On the valley floor, primarily alluvial soils with silty-clay composition of marine origin, with good fertility. Hillsides show more clay-loam and stony-clay composition, mostly marine in origin, with some volcanic outcropping, and less fertility. Principal varieties & characteristics: Cabernet Sauvignon, Merlot, Cabernet Franc: Cabernets usually reveal a lush yet firm texture with good acidity, firm tannin and distinctive cherry-blackberry flavors. Merlot typically has vibrant black cherry flavors mixed with a touch of cocoa.

Coombsville AVA
Climate: Temperate climate moderated by near-proximity to the San Francisco Bay and the influences of marine air. Elevation: Most vineyards are in the 100-500 foot (30-150 m) zone, though a small portion tops 1000 feet (300 m). Rainfall: Average rainfall is 24.6 inches (62 cm) per year over the last 100 years. Soils: Primarily weathered volcanic rock and alluvial deposits from the Vaca Range that surrounds the region. Principal varieties: Dominated by Cabernet Sauvignon on the hillsides with Merlot, Chardonnay, Syrah and Pinot Noir in the lower, cooler sites

Diamond Mountain District AVA
Climate: Moderately warm temperatures with lower maximum temperatures and higher minimum temperatures than north Napa Valley floor, due to topography and altitude. Significantly cooler than valley floor near Calistoga, 50 to 95°F in growing season (10 to 32°C). Elevation: 400 to 2200 ft. (130 to 530m). Rainfall: 40 to 55 inches (135cm) annually. Soils: Residual uplifted soils of volcanic origin, often reddish and very fine-grained, even gritty in texture, composed of both weathered sedimentary and volcanic origin. Principal varieties & characteristics: Cabernet Sauvignon, Cabernet Franc: firmly structured, rich and fairly tannic when young, with strong blackcurrant, mineral, and cedary flavors. Less supple and fleshy than valley or benchland wines, with good aging potential. Chardonnay: Full-bodied, yet revealing mineral, green apple-peach aromas with fairly firm acidity; less richly textured than valley floor wines.

Howell Mountain AVA
Climate: Similar to the facing Spring Mountain AVA, however slightly warmer and dryer overall due to strong afternoon sun influence. Fairly cool nights in both ranges and higher elevations help maintain good acidity. Elevation: 600 to 2200 ft (184 to 675m). Rainfall: 40 to 50 inches (125cm) annually. Soils: Predominantly volcanic, shallow and infertile. Drainage is high, fertility low. Principal varieties & characteristics: Cabernet Sauvignon, Merlot, Zinfandel: Powerful, firm, blackberry-currant flavors and often richly tannic, with excellent acidity for aging. Chardonnay, Viognier: Sinewy, firm and not as fruity as those of the valley floor, revealing more citrus and stone fruit flavors.

Los Carneros AVA
Climate: Cool, with prevailing marine winds from the San Pablo Bay and through the Petaluma Gap to the west. High temperatures during summer rarely exceed 80°F (27°C) with less diurnal range variation. Elevation: 15 to 400 ft. (4.6 to124 m). Rainfall: Lowest in Napa Valley: 18 to 24 inches (7.2 to 9.6cm) annually. Soils: Clay dominated, very shallow in general, with more loam and hillside alluvials in the northern section. Yields typically are restrained by the hard claypan subsoil, which prevents deep-rooting. Principal varieties & characteristics: Chardonnay: minerally pear-apple and spice flavors. Merlot: sinewy and lightly herbal, with fine tannins and sleek structure. Pinot Noir: ripe cherry-cinnamon spice flavors with earthy notes.

Mount Veeder AVA
Climate: Cool to moderate, with most vineyards above the fog-line, meaning warmer nights and cooler days and less diurnal range than the valley floor. Typical mid-summer high temperatures about 85°F (30°C). Elevation: 600 to 2100 ft. (183 to 650m). Rainfall: 35 inches (87.5cm) annually. Soils: Sedimentary based, former seabed, shallow and generally well drained, as well as more acidic, with low fertility. Most have a sandy or sandy-loam texture. Principal varieties & characteristics: Ageability is a hallmark of Mt. Veeder wines. Cabernet Sauvignon, Merlot, Zinfandel: Low yields give red wines a firm, tannic structure with strong earth-berry aromas and rich, but powerful flavors. Chardonnay: minerally, appley, even citrus flavors with good acidity.

Oak Knoll District of Napa Valley AVA
Climate: Moderate to cool: marine air and fog can remain until mid-morning. Late afternoon breezes frequently occur, maintaining slightly cooler temperatures than upper valley. Mid-summer temperatures may reach 92° F (33.3°C) and drop to around 50°F (10°C) at night. Elevation: sea level to 800 feet (244m). Rainfall: 36 inches (90cm) annually. Soils: The valley’s largest alluvial fan formed by Dry Creek creates the defining feature of the district. The northwest area is composed of volcanically derived soils, with stony or gravelly consistency. South and east areas are transitional from gravel to silty clay loam. Principal varieties & characteristics: Merlot, Chardonnay and Cabernet Sauvignon. Merlot and Cabernet Sauvignon benefit from a longer growing season with slightly cooler temperature, though crop size is typically less than in other AVAs. Elegant style is the common note with fruit flavors of cassis, tobacco and spice typical to Bordeaux-style reds. Chardonnay showcases flavors of crisp apple, mineral notes and tropical fruit with fine acidity.

Oakville AVA
Climate: Moderately warm, with temperatures commonly in the mid-90°F (34-35.5°C) range in high summer, but also still strongly affected by night and early morning fog which helps keep acidity levels good. East side of the AVA receives more of warmer afternoon sun. Elevation: 75 to 500 ft (23 to 150m). Rainfall: 35 inches (87.5cm) annually. Soils: Primarily sedimentary gravelly alluvial loams on the western side, with more volcanic but heavier soils on the eastern side. Low to moderate fertility and fairly deep, with average water retention. Principal varieties & characteristics: Cabernet Sauvignon, Merlot: Ripe currant and mint flavors, rich texture and full, firm structure tempered by rich fruit. Sauvignon Blanc: Full, steely, yet very fleshy.

Rutherford AVA
Climate: Moderately warm, still marginally influenced by early morning fog. Western bench area is cooler, with less late afternoon sun, tempered by afternoon marine winds. (This AVA averages a bit warmer than Oakville and Stags Leap District). Usual summer peak temperatures are mid-90°F (34-35.5°C) with good diurnal range. Elevation: 100 to 500 ft. (33 to 150m). Rainfall: 38 inches (95cm) annually. Soils: Western benchland is sedimentary, gravelly-sandy and alluvial, with good water retention and moderate fertility. The eastern side has more volcanic soils, moderately deep and more fertile. Principal varieties & characteristics: Cabernet Sauvignon, Merlot, Cabernet Franc, Zinfandel: Quite intense cherry and mineral, almost earthy aromas. Flavors are full, ripe, and notably currant with firm, but supple tannins for extended aging.

Spring Mountain District AVA
Climate: Similar to Mt. Veeder AVA, with cool weather prevailing and smaller diurnal changes. Fairly cool nights and higher elevations help maintain good acidity. Elevation: 600 to 2200 ft (184 to 675m). Rainfall: 40 to 50 inches (125cm) annually. Soils: Primarily sedimentary; weathered sandstone/shale, loamy and friable in texture. Drainage is high, fertility low. Principal varieties & characteristics: Cabernet Sauvignon, Merlot, Zinfandel: Powerful, firm, blackberry-currant flavors and often richly tannic, with excellent acidity for aging. Chardonnay, Viognier: Sinewy, firm and not as fruity as those of the valley floor, revealing more citrus and stone fruit flavors.

St. Helena AVA
Climate: Warm, due to greater protection from western hills, with less fog or wind incursions. This narrowest part of the Napa Valley floor floor provides more heat reflection off the hillsides. Mid-summer temperature peak is often in the 85 -90°F range (30 to 35°C). Elevation: 150 to 5 00 ft. (46 to 152 m). Rainfall: 38 to 40 inches (95 to 101 cm) annually. Soils: South and west borders are more sedimentary, gravel-clay soils, with lower fertility and moderate water retention. Further north and to the east soils are prevalently volcanic in origin and are deeper and more fertile. Principal varieties and characteristics: Cabernet Sauvignon, Cabernet Franc, Merlot: deep, ripe, often jammy flavors, with firm tannins for structure and acid for long cellaring. Appealing aromas of currant and black fruit. Syrah, Viognier: Fleshy, supple and slightly earthy. Zinfandel: Blackberry-like, well-structured. Sauvignon Blanc, fresh and forward, passion fruit and lemon, crisp and fresh, not “grassy.”

Stags Leap District AVA
Climate: Moderately warm, with afternoon marine winds acting as an ‘air-conditioner’ to cool the warmer air radiating off the bare rocks of Stags Leap itself and the surrounding hillsides. This AVA is often up to 10°F warmer than in Yountville AVA. Mid-summer temperatures can reach 100°F (37.7°C), but more regularly are in mid-90° range (32-34°C). Elevation: 66 to 400 ft. (20 to 123m). Rainfall: 30 inches (75cm) annually. Soils: Volcanic gravel-loams on the floor of the valley, with rocky hillsides, and low to moderate fertility due to hard clay bedrock subsoils 2 to 6 feet down. Principal varieties & characteristics: Cabernet Sauvignon, Merlot, Sangiovese: Distinguished by lush, velvety textures and fine perfumed cherry and red berry flavors, supported by soft tannins. Chardonnay, Sauvignon Blanc: Round and ripe, especially Sauvignon Blanc, yet retain excellent citrus and apple flavors.

Wild Horse Valley AVA
Climate: A warmer area well to the east of Napa Valley proper, but still moderated by both altitude and prevailing winds coming off Suisun Bay to the southeast. Elevation: Wild Horse Valley 400 to 1500 ft. (123 to 460m). Rainfall: 35 inches (94cm) annually. Soils: Volcanic in origin, with basaltic red color, shallow with limited water retention, so irrigation is often essential. Principal varieties & characteristics: Cabernet Sauvignon, Sangiovese: Bright berry and cherry fruit, and more acidity than wines from Stags Leap District. Chardonnay: Crisp, floral, aromatic, with distinctive pear-mineral flavors and bright acidity.

Climate: Moderate, with definite cool marine influence and fog contributing to cool summer mornings and the marine breeze keeping afternoons more comfortable than further up valley. Mid-summer peak temperatures may reach 90°F (32.2°C), with noticeable diurnal fluctuation to the mid-50°F range (13°C). Elevation: 20 to 200 ft (6 to 61m). Rainfall: 32 inches (80cm) annually. Soils: Principally gravelly silt loams, sedimentary in origin, and gravelly alluvial soils with rock, moderately fertile. Principal varieties & characteristics: Cabernet Sauvignon, Merlot: Yountville favors Cabernet and Merlot with ripe, violety aromas and rich, but supple flavors and firm tannins.

The North Coast American Viticultural Area (AVA) in California also covers Mendocino and Lake counties, and portions of Marin and Solano counties which are not detailed herein.