Impersonal conditions don't have to relate to the weather, of course. One of my favorite examples, from a friend of mine in China, read somewhat as follows:
Plenas je homoj en la cxambro.This is one way of expressing that the room is full of people. Literally: "It is full with people in the room." In Esperanto, this subjectless sentence is a perfectly good way of expressing this condition -- here the emphasis is on the general environment, rather than on a condition of the room.