Under the Köppen climate classification, Bamako features a tropical savanna climate (Köppen ''Aw''). Located in the Sudano-Sahelian zone, Bamako is very hot on average all year round with the hottest months being between March and May. The mildest months are between November and February. During the dry season, rainfall is scarce: virtually none falls between November and April due to the dominance of the Saharan anticyclone and the dry trade winds. The rainy season occurs in the summer with the peak occurring with a few storms beginning in May, then transitioning to the monsoon from June to October.