Sometimes when we went to school in the morning, on foot to junior school, or on bicycles to grammar school, it would be foggy. Humberston and Cleethorpes were on the coast, and sometimes sea mists would envelop the town. Sometimes it would be fog, or a mixture of the two. We would wrap up well because such days were usually cold and clammy. On very rare occasions they were not, and we would step outside to find the day unnaturally warm, despite the mist. With delight at the unexpected warmth, we referred to such days as “oven days” because it felt like stepping into a warm oven.
On oven days the mists were exceptionally thick, with visibility down to a few feet. If one of us raced a few feet ahead, they disappeared from view. The other unusual feature was the way they deadened sounds, giving them a dull, muffled feel. It made crossing street corners quite hazardous, but fortunately such traffic as had ventured out crawled along slowly with all lights blazing.
I read they are probably advection mists, in which warm moist air flows over a cool surface, such as a cold sea, forming a thick mist that can then blow in from the sea. I suppose it happened perhaps a couple of times per winter. The rest of the foggy days were unpleasantly cold and damp, but the oven days were a positive pleasure. It was quite exciting to make one’s way through such limited visibility without feeling uncomfortably cold. We left bikes at home on such days and walked to school, thinking it too dangerous to be on the roads.