Summer in Sonoma County

Sonoma County's hottest months are typically July and August, with average highs ranging from the mid-80s to low-90s°F. Inland areas like Alexander Valley, Sonoma Valley and Dry Creek Valley can see temperatures climb into the mid-90s and beyond, while the Sonoma Coast remains cooler, moderated by ocean breezes and morning fog. To prepare for the summer heat, check out 10 Cool Things to Do in Sonoma County When It’s Hot Outside.

Yes, summer fog is a defining feature of Sonoma County's climate. Cool, moist air from the Pacific Ocean rolls in through coastal gaps — most notably the Petaluma Gap — bringing morning fog to coastal areas and the lower valleys. This fog typically burns off by midday, giving way to sunny afternoon skies before returning in the evening.

Fun fact: This summer fog cycle of warm days and cool nights is an important ingredient in Sonoma County winegrowing, as it enables winegrapes to ripen slowly and develop complex flavors.

While any month is a great time to visit Sonoma County, the summer months bring lush, green vineyards, sunny days that invite outdoor activities, the return of the Regional Parks River Shuttle, and tons of concerts, festivals, and winery events.

Month by month, here’s a taste of summer in Sonoma County:

June
June brings the North Coast Wine and Food Festival, the weekend-long Petaluma Fair, and the Big West Wine Fest, the largest gathering of California natural winemakers, while the Country Summer Music Festival takes the stage at the Sonoma County Fairgrounds. June is also Lavender Month in Sonoma County, unfurling in fields of purple blooms. The kid-friendly Water Park at Spring Lake in Santa Rosa’s Spring Lake Regional Park re-opens for the summer, and expanded hours begin at Glen Ellen’s Morton’s Warm Springs Resort. Summer-long series of free, family-friendly events include Summer on the Square in Downtown Santa Rosa, and being PRIDE Month, the LGBTQ+ community is celebrated throughout the county. For specific event details, check out our Calendar of Events.

July
Fourth of July fireworks and events are held all over the county, and the following week, the colorful Sonoma County Hot Air Balloon Classic takes to the skies in Santa Rosa. Guerneville celebrates both Gay Wine Weekend and Lazy Bear Week, and Petaluma hosts its annual Petaluma Art & Garden Festival and the quirky Rivertown Revival Festival. Sonoma State University’s Green Music Center opens its back wall and once again invites lawn seating, while over in Sonoma, the Valley of the Moon Music Festival is held at multiple venues. For specific event details, check out our Calendar of Events.

August
The huge, week-long annual Sonoma County Fair returns to the Sonoma County Fairgrounds with rides, food, exhibits and much more. You can also kick up your heels at the Cotati Accordion Festival, enjoy apple treats at Sebastopol’s Gravenstein Apple Fair, and sing along to Sonoma’s Broadway Under the Stars musical theater series. For specific event details, check out our Calendar of Events.

Yes, good campgrounds and RV parks can be found all over Sonoma County, from beach campgrounds along the Sonoma Coast to boating campsites at Lake Sonoma. Whether you’re interested in dog-friendly camping, family-friendly camping or even luxury glamping, Sonoma County offers beautiful Wine Country camping spots amid redwoods, rivers, mountains, and the Pacific Ocean.

Labor Day Weekend in Sonoma County brings warm, sunny weather, the start of harvest season, and plenty of things to see and do. You can explore the stunning Sonoma Coast, paddle or swim in Sonoma County rivers, or do some fishing in area parks. Take a stroll through the redwood-shaded Grove of Old Trees or go cycling through Sonoma County. Book some terrific garden, vineyard or winery tours, or simply check out wineries with fun things to do. Labor Day Weekend is also your last chance to splash around the Rio Nido Roadhouse Pool and the Water Park at Spring Lake.