Saipan has a borderline tropical rainforest climate (Köppen ''Af'')/tropical monsoon climate (Köppen ''Am''), moderated by seasonal trade winds from the northeast from November to March, and easterly winds from May to October. Average year-round maximum temperature is . There is little seasonal temperature variation, and Saipan has been cited by the Guinness Book of World Records as having the least fluctuating temperatures in the world. However, the temperature is affected by elevation; hence, the island shows considerable variations between the coastal and mountainous areas.