Prevailing oceanic trade winds from the Canary Islands modify the influence of the harmattan, producing a humid but temperate climate. Rainfall here is minimal; in Nouadhibou it averages less than three centimeters annually and occurs between July and September. Temperatures are moderate, varying from mean maximums of 28°C and 32°C for Nouadhibou and Nouakchott, respectively, to mean minimums of 16°C and 19°C.