Month: January 2019

Why San Francisco fog has been so low

Posted by – January 13, 2019

The Bay Bridge sinking into Karl the Fog last Thursday

I’ve gotten used to seeing Treasure Island and Oakland vanish into the fog since we switched coasts, but this past week offered something I hadn’t noticed before. The Bay Bridge poked its way out of the fog, while its lower half looked like someone had swiped a Photoshop blur brush across everything close to the water (as seen above in the photo I took from the Financial District). It was beautiful, but it did get me wondering about why the fog behaves in different ways. Then — lo and behold — an answer showed up in my RSS feed. As SFGate explained, the cause and effect are pretty simple: cold stays low, and during the current time of year, the fog is filled with cooler air than the summer months when the fog reaches higher.

Specifically, this fog is now “coming from Central Valley while the fog that’s higher in the atmosphere and typical in summer months is formed over the Pacific Ocean.” Great to know.