What does it mean to dream about fog?
Fog usually points to confusion or a loss of clarity, a time when the way ahead is hard to see and you must move slowly.
Four ways to read it
Each reading below comes from a named tradition and a cited source, so you can see where it came from and decide what fits your dream.
Freud
Freud would read fog as a screen the mind draws over something, blurring what it does not wish to see plainly. What lies just beyond it may be the real concern. The wish to look, or not to, is part of it.
After Freud, The Interpretation of Dreams (Brill trans., 1913), public domain.Jung
Jung would see fog as the threshold of the unconscious, a place where the familiar dissolves and the unknown begins. It can mark a passage one must feel through rather than see. Patience is the way across it.
Jungian concept (our summary).Modern
Continuity ties fog to waking confusion or indecision, a sense of not knowing the way forward. It often follows a stretch of unclear or overwhelming days. The dream tends to mirror that haze rather than resolve it.
Continuity hypothesis (our summary).Mythological
Heroes were hidden in mist by their patron gods, and whole islands were veiled by enchantment in Celtic story. Fog marked the border between the seen world and the otherworld. To enter it was to pass between realms.
Rosmerta Publishing editorial synthesis (after Bulfinch; Brewer).