Indonesia has a typical equatorial climate with two seasons: rainy and dry. Starting in September, cool Northwesterly winds pick up moisture while crossing the South China Sea. The wet season lasts from about November to March. The tropical climate varies from islands to islands. Temperatures are uniformly high and are a function of elevation rather than latitude. They are highest along the coast, where mean annual temperatures range from 74 to 88 °F (23 to 31 °C).