Per the U.S. Dept of Agriculture (USDA), the 2024 California wine grape crush was the smallest in 25 years. Total crush size was 2.844 million tons, a 23% decline for 2023's 3.7 million tons. Average grape prices fell 5%, but the previous year was the highest ever, so not really a meaningful decline.
These numbers are state-wide. Three-fourths of California's wine grapes come from the Central Valley. Napa and Sonoma Counties are each about 4% of the state's total.