California Fall Color has a fall color report for agricultural areas including vineyards in Sonoma County near Petaluma:
30 – 50% – Petaluma Agricultural Areas – Vineyards along the Lakeville Highway, south of Petaluma were showing deep red to yellow. Cottonwood were yellow-orange. Occasional nut trees and exotics were coloring from yellow to firey orange. Pumpkin farms were full of bright orange pumpkins.
Go to California Fall Color to see photos and more reports.