The humid subtropical climate is often located on the western side of the subtropical high. Here, unstable tropical airmasses in summer bring convective overturning and frequent tropical downpours, and summer is normally the season of peak annual rainfall. In the winter (dry season) the monsoon retreats, and the drier trade winds bring more stable airmass and often dry weather, and frequent sunny skies. Areas that have this type of subtropical climate include Australia, Southeast Asia, and parts of South America. In areas bounded by warm ocean like the southeastern North America and East Asia, tropical cyclones can contribute significantly to local rainfall within the subtropics. Japan receives over half of its rainfall from typhoons.