It has been windy here lately. I don't really have air conditioning, but I do have windows on both the east and west sides of my apartment. When the wind is out of the east or west, I can get great cooling by opening both sides. When the wind is out of the north or south, cooling my apartment becomes very difficult.
It has got me thinking about the old dungeon winds that would extinguish torches, and were good reasons for a protected lantern. I've been wondering - were the old dungeon winds random? Or did they arise from features that players might predict from the presence of airflow? If one wanted to explain dungeon winds (or just moving air at all), how might one do it?
An opening near the surface might admit a draft of fresh air. A pair of dungeon entrances at different elevations could produce a regular flow with both an influx and and outflux, like prairie dog burrows do. A big persistent fire in the dungeon might have an in-draft and an outflow. A tidal dungeon, where sections fill or empty of water, would have air flows associated with that. The breathing of an enormous beast could produce regular periodic air flows. A deep, cold underworld might have inflows where air in the upper levels cools and sinks. You might be able to tell which doors are open or closed based on air flows; you can sure tell whether my windows are open or closed based on them. Monsters might also be able to tell by the direction of drafts where things have changed in their environment...
(There are, of course, plenty of other interesting features to air besides motion - temperature, humidity, smell, composition... and all of these could signal features too)