Fresno, CA – Drivers across the Central and Southern San Joaquin Valley should prepare for slow and hazardous travel early Wednesday as dense fog fills in before sunrise.
According to the National Weather Service in Hanford, a Dense Fog Advisory remains in effect from 3 AM to 10 AM Wednesday, affecting a wide stretch of the valley from Los Banos and Merced south through Fresno, Visalia, Delano, and Bakersfield. Visibility is expected to drop to a quarter mile or less in many areas, creating dangerous commuting conditions.
Forecasters say conditions will deteriorate rapidly after 3 AM as radiational cooling and calm winds allow thick fog to form. The fog may be most widespread along major corridors including Highway 99, Interstate 5, and surrounding rural roadways where cold ground temperatures trap moisture near the surface.
According to the NWS, dense fog will peak around sunrise, lingering through mid-morning before gradually lifting as daytime heating increases visibility. Drivers should anticipate sudden visibility drops, especially in low-lying areas and agricultural zones near canals and open fields.
Impacts may include slowed traffic, poor visibility at intersections, and difficulty spotting stopped or merging vehicles. Commuters, early-shift workers, and school transportation services should use caution and allow extra travel time.
The NWS urges motorists to slow down, keep headlights on low beam, and leave additional distance between vehicles. Those traveling long distances should monitor updates before heading out, as fog can form and dissipate unevenly across the valley.
