Fog is essentially a cloud that forms at ground level. It develops when the air near the surface cools to the dewpoint, the temperature at which the air becomes saturated with moisture. When this ...

Add Yahoo as a preferred source to see more of our stories on Google. We have been under a foggy and chilly pattern for nearly three weeks across the Bay Area. High pressure centered off the ...

California’s Central Valley has spent the past several weeks buried under a thick, unmoving layer of tule fog — the dense, ground‑hugging haze that can turn I‑5 and Highway 99 into walls of white with ...