Sonoma and Napa Valley started the day under dense fog, with early morning temperatures in the low 40s. Meteorologists say the marine layer should gradually lift by late morning, allowing clearer skies in lower elevations and afternoon highs near 64°F. After sunset, patchy fog is expected to return, with overnight temperatures dropping back to around 40°F.
Morning Fog, Afternoon Sunshine
Widespread fog is forecast to persist until about 10 a.m., reducing visibility on local roads during the morning commute. Conditions should improve by midday, with skies turning mostly cloudy to partly sunny. Afternoon temperatures will peak near 64°F, then cool slightly into the low 60s. Winds will remain light early, becoming west-northwest at 5 to 10 mph later in the day, according to the National Weather Service (NWS) in San Francisco.
Breezes Increase Later in the Day
By afternoon, light winds will help clear lingering low clouds without becoming disruptive. Outdoor plans should be mostly unaffected, though conditions offshore and along the coast will be choppier. Coastal waters may see rougher seas, which could impact boating and shoreline activities.
Coastal Flooding and Beach Hazards
A Coastal Flood Advisory remains in effect until noon Sunday for low-lying areas along the San Francisco and San Pablo Bays. Minor flooding is possible in bayside parks, parking lots, and roads during peak high tides.
Along the outer Pacific Coast, a Beach Hazards Statement continues through Sunday due to long-period swells. These conditions can create large breaking waves and dangerous sneaker waves. Officials urge the public to stay off jetties and piers and avoid entering the water.
Commute and Boating Safety
Drivers should use low-beam headlights in fog, reduce speed, and allow extra stopping distance—especially near bridges and bayshore routes. Those parked near the water should watch for shallow flooding around high tide and avoid driving through standing water.
Boaters are advised to check the latest marine forecasts and respect any small craft advisories before heading out, as sea conditions may change quickly.
Looking Ahead
A weak ridge of high pressure is expected to bring slightly warmer conditions from Monday through Wednesday, with daytime highs climbing into the mid to upper 60s. Morning fog will likely continue in valleys and areas near the bay. No significant rain is expected in the near term, though forecasters recommend staying alert for updates in case advisories change.