Hanford, CA – A Dense Fog Advisory has been issued for most of the San Joaquin Valley early Wednesday, with forecasters warning of dangerously low visibility along Interstate 5 and other major travel corridors. The National Weather Service in Hanford says dense fog is expected between 3 a.m. and 10 a.m. Wednesday, creating high transportation risks across Central California.
According to the weather service, clearing skies overnight will allow fog to form rapidly across the valley floor, affecting key north–south routes including I-5, Highway 99, Highway 41, Highway 43, Highway 198, and Highway 180. Visibility may drop to 200 feet or less in some locations, particularly before sunrise.
Forecasters emphasize that the highest risk areas include stretches of I-5 between Kettleman City, Los Banos, Coalinga, and the Harris Ranch region, where tule fog commonly develops during early winter. Drivers may encounter abrupt visibility drops, prompting sudden slowdowns and possible travel delays.
The weather service’s transportation risk assessment places the San Joaquin Valley in a Level 4 – High Impact category for Wednesday morning, indicating elevated danger for commuters, commercial truck drivers, and agricultural traffic.
Motorists are urged to slow down, use low-beam headlights, maintain extra distance between vehicles, and avoid passing in foggy conditions. Travel may be especially hazardous at freeway interchanges, rural two-lane roads, and bridges where visibility tends to drop sharply.
Fog is expected to gradually lift late Wednesday morning as daytime heating increases, though pockets of lingering fog may persist in low-lying areas and near irrigation zones.
Travelers can monitor updates from NWS Hanford and check CHP and Caltrans reports for real-time road conditions throughout the morning.
