Fogbows are pale rainbows made when sunlight passes through tiny fog droplets.

The longer version

A fogbow appears when sunlight passes through the extremely small droplets that make up fog. The light is bent, reflected inside each droplet, and bent again on the way out, much as with an ordinary rainbow, but the droplets involved are far smaller.

Because they are so tiny, wave effects dominate: the colours overlap and wash out, leaving a broad pale arc that is mostly white with faint reddish and bluish edges. Fogbows are sometimes called white rainbows and they appear when the sun is low and behind the observer, often over open water or a frosty field.

Where this entry sits

Clouds, wind, rain, and storms shape daily life in ways that most people barely notice. This collection explains snow, lightning, rainbows, the turning seasons, temperature, the instruments forecasters rely on, and scraps of old weather lore. The full list sits on the Weather and Climate page, where every entry is listed in order.