A breathtaking natural phenomenon appeared over the Pacifica Municipal Pier in the San Francisco Bay Area on Monday, September 15 — a rare “fogbow.”

Unlike traditional rainbows, a fogbow forms when tiny water droplets in fog scatter sunlight, creating a pale or white arc across the sky. According to the National Weather Service (NWS), the effect is sometimes called a “white rainbow,” and is far less common than its colorful counterpart.

Locals described the sight as surreal, as the ghostly arc stretched above the pier against a backdrop of thick coastal fog. Photos and videos of the event quickly spread online, drawing fascination from weather enthusiasts and casual observers alike.

The appearance of the fogbow highlighted the unique atmospheric conditions along the California coast, where fog often plays a dramatic role in shaping the landscape’s beauty.