Fogbows are closely connected to rainbows.
They are created by almost the same process – but with tiny water droplets within the fog rather than larger raindrops.
Fogbows – also referred to as white rainbows, cloudbows, or ghost rainbows – are created almost like rainbows, from the same combination of sunshine and moisture. Rainbows appear when the air is full of raindrops. Moreover, we always see rainbows in the opposite direction of the sun.
Almost the same happens with fogbows – they are always opposite the sun.
However, fogbows are formed by tiny droplets within the fog or cloud rather than by bigger raindrops.
You can see fogbows in a thin fog while the sun is shining. You could see one as the sun emerges above the clouds. Over the ocean is a good choice as well.
Since the water droplets in the fog are so tiny, fogbows have either soft colors or are colorless.
Les Cowley (who runs the amazing website Atmospheric Optics) tells:
Look away from the sun and at an angle of 35-40 degrees from your shadow which marks the direction of the antisolar point. Some fogbows have very low contrast so look for small brightenings in the misty background. Once caught, they are unmistakable.
The sun must be less than 30-40 degrees high unless you are on a hill or high up on a ship where the mist and fogbow can be viewed from above.
Fogbows are huge, almost as large as a rainbow and much, much broader.
To conclude: Fogbows are formed in almost the same way as rainbows. But, with tiny water droplets within the fog instead of larger raindrops. Since the water droplets in the fog are so thin, the fogbows have soft colors or are colorless.