Rains are abundant, exceeding 2 m a year. The rainfall is caused by the Stau effect that occurs within depressions, causing strong southern winds and forcing air to rise along the slopes of mountains and to release its humidity as precipitation. During the winter precipitation often falls as snow. Winter is a relatively drier season, while the other three seasons have a uniformly high humidity, with the exception of the dry month of July. Fog may appear for a few days a year.