And on this most Welsh of days, the weather has joined in by providing us with white mist. Remarkably white, actually - not the gray and murky mist one so often gets round here.
For me the Festival of Fog is supremely about our state of unknowing, and how much better un-knowing is than knowing. For in the daylight we can see clearly. In the dark we can't see at all. The latter is a disaster, as we wander around bumping into things; the former devoid of romance and mystery as things appear in their ghastly clarity.
But fog, like snow, brings a glamour and transformation to everything. In the dark, God is Dead - he cannot be seen, touched or heard by worldly eyes, hands or ears. In the light - there are his demands! Hard, testing demands that we cannot live up to; and an alternative that says we give up all hope in our own abilities.
But in the fog there's a world of half-truth and paradox; of groping for the truth and then discovering you've just accidentally stroked the face of a passing copper.
In the fog, we've just enough sight not to trip over obstables nor walk into trees. But further off the reality becomes more blurred. A dim figure in the middle-distance could be an angel, a postman or a tree stump. The dull stomping you hear could be blokes working on the road to Aspley - or the Crack of Doom opening. The rumble of the traffic on the M1 morphs into the rushing of many waters.
So let us celebrate uncertainty, and come down uneqivocally for doubt. And may the words of our hearts reflect the fog in our heads in this most imprecise of all weathers.