Sonoma in September

April through June gives you perfect weather without the crowds. Temperatures hover in the 70s, wildflowers bloom across hillsides, and most wineries operate normal hours without the summer rush. May is particularly sweet — you'll catch the end of mustard flower season painting vineyards yellow. September and October bring harvest season with warm days and cool nights. This is peak time for wine enthusiasts who want to see crush in action, but expect higher prices and busy tasting rooms. Book accommodations months ahead for harvest weekends. Summer means guaranteed sunshine but also means traffic, crowds, and temperatures that can hit the 90s. Many wineries require reservations during summer months. Winter offers the best deals — hotel rates drop 30-40% and restaurants have availability. But some smaller wineries close or reduce hours, and rain can disrupt outdoor activities. December through February sees the most precipitation, though storms usually pass quickly. The shoulder seasons of late fall and early spring provide the best balance of weather, availability, and reasonable prices.