San Ysidro District AVA
San Ysidro
A cool foothill enclave in southeastern Santa Clara Valley, supplying fruit to the region's wineries since 1990.
San Ysidro District AVA is a 2,340-acre sub-appellation nestled in the Diablo Range foothills of Santa Clara Valley. Established in 1990, it operates purely as a fruit source, with no wineries located within its boundaries. Pacific fog and breezes channeled by the Pajaro River make it significantly cooler than surrounding areas.
- Total area of 2,340 acres (947 hectares) in the southeastern corner of Santa Clara Valley
- Established as an AVA in 1990; named after Saint Isadore the Laborer, patron saint of farmers
- Located in the foothills of the Diablo Range, with gravelly, well-draining soils
- Climate is warm-summer Mediterranean, rated Region I-II, and notably cooler than most of Santa Clara Valley
- Cooling influence comes from Pacific fog and breezes that travel inland along the Pajaro River
- No wineries exist within the district; all grapes are sourced by Santa Clara Valley producers
- Nested sub-AVA within both Santa Clara Valley AVA and the broader San Francisco Bay AVA
Location and Status
San Ysidro District is a nested American Viticultural Area sitting within the larger Santa Clara Valley AVA, which itself falls under both the San Francisco Bay AVA and the Central Coast AVA. The district occupies the foothills of the Diablo Range in the southeastern portion of Santa Clara Valley, covering 2,340 acres of elevated, foothill terrain.
- Sub-AVA within Santa Clara Valley, San Francisco Bay, and Central Coast appellations
- Positioned in the foothills of the Diablo Range, southeastern Santa Clara Valley
- Total vineyard area of 2,340 acres (947 hectares)
- Named after Saint Isadore the Laborer, patron saint of farmers
Climate and Soils
The district's climate is warm-summer Mediterranean, rated Region I-II on the UC Davis heat summation scale. It is significantly cooler than other parts of Santa Clara Valley, a distinction driven by Pacific fog and cool breezes that funnel inland along the Pajaro River corridor. Soils in the Diablo Range foothills are gravelly and well-draining, well suited to viticulture.
- Warm-summer Mediterranean climate, classified Region I-II
- Cooler than the broader Santa Clara Valley due to Pajaro River fog and breeze corridor
- Gravelly, well-draining foothill soils support vine health and fruit concentration
- Pacific maritime influence moderates temperatures throughout the growing season
Grape Growing and Wine Style
San Ysidro District grows Cabernet Sauvignon, Chardonnay, Pinot Noir, and Merlot. The AVA functions entirely as a fruit source; there are no wineries within its boundaries. Grapes harvested here are vinified by producers based elsewhere in Santa Clara Valley, where the cooler foothill conditions contribute distinct character to the finished wines.
- Principal varieties: Cabernet Sauvignon, Chardonnay, Pinot Noir, and Merlot
- No wineries operate within the AVA itself
- All fruit is supplied to wineries in the broader Santa Clara Valley
- Cooler temperatures relative to the valley floor support longer hang time and flavor development
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Open Wine Lookup →History
The San Ysidro District AVA was established in 1990. Its name honors Saint Isadore the Laborer, the patron saint of farmers, reflecting the agricultural heritage of the region. The district sits as one of the smaller, more specialized appellations in California, defined primarily by its distinct climatic and geographic separation from the broader valley floor.
- AVA status granted in 1990
- Named for Saint Isadore the Laborer, patron saint of farmers
- One of the smaller AVAs in the greater Santa Clara Valley system
- Established to recognize the cooler, distinct conditions of the Diablo Range foothills
Fruit sourced from San Ysidro District reflects the cooler foothill climate, with Cabernet Sauvignon and Merlot showing structured tannins and focused dark fruit, while Chardonnay and Pinot Noir benefit from retained acidity and elegance compared to warmer valley floor expressions.
- Kirigin Cellars Estate Chardonnay Santa Clara Valley$15-20Santa Clara Valley producer drawing on cool-climate foothill fruit; accessible expression of the region's Chardonnay.Find →
- Enzo Vineyards Pinot Noir Santa Clara Valley$25-35Santa Clara Valley Pinot Noir showing the cooler-climate character typical of Diablo Range foothill sources.Find →
- Clos LaChance Cabernet Sauvignon Santa Clara Valley$30-45Established Santa Clara Valley producer using foothill fruit; structured Cabernet with focused dark fruit character.Find →
- San Ysidro District AVA established 1990; nested within Santa Clara Valley, San Francisco Bay, and Central Coast AVAs
- Area: 2,340 acres (947 hectares) in the foothills of the Diablo Range, southeastern Santa Clara Valley
- Climate: warm-summer Mediterranean, Region I-II; cooler than surrounding valley due to Pajaro River fog and Pacific breezes
- Soils are gravelly and well-draining; principal grapes are Cabernet Sauvignon, Chardonnay, Pinot Noir, and Merlot
- No wineries located within the AVA; operates solely as a fruit source for Santa Clara Valley producers