Various ceiling fans are used in both summer and winter.
In summer, the fan's rotation direction is set so that it blows air downward. This cools off people more quickly.
In the winter, when many buildings are heated (in colder climates), the fan is used to push warm air downward. The fan's rotation direction is set so that it pulls cold air up to the ceiling, which forces the warm air that originally rose to be pushed to the lower levels of the room.