Sounds travel farther in fog. I hear the distant neighbor's rooster more clearly; the sound of the train's whistle is almost on the porch in spite of the fact it's miles away. The screech owl's plaintive trill is more haunting, almost painful, somehow touching a chord of mournfulness and longing.
As a child, I lived on Puget Sound in Washington State. We were fortunate to reside on a bay called Dyes Inlet. There, fog was a frequent visitor, and I remember the mist as a friend (not having to drive in it as a child!), feeling safe, tucked in. Perhaps that's why I also love Carl Sandburg's poem...which I've toyed with (below) to move it from a city by the sea to my West Virginia mountains...
The fog comes
on little cat feet.
It sits looking
over [fields and fences] harbor and city
on silent haunches
and then moves on.
Carl Sandburg (1878-1967)