You walk into loads of areas that not governed by outside conditions as well lofts.
Swimming pools, bakers, air conditioned restaurants, trains
If the moisture from anything hits a cooler surface it condenses, if the moisture content in the air is high then there is no where for it to go, then it stays put as sweat on your skin or wet droppings in the loft, if you walk in from outside your glasses, if you wear them, then the moisture condenses on them :-/