Most important are the Pampanga, Agno, Cagayan, and Pasig on Luzon and the Angusan and Mindanao on Mindanao. Temperatures vary more between day and night and high and low altitudes than between seasons. The eastern part of the country gets most of its rainfall between October and April from the winter or northeast monsoon. By contrast, the western portion receives most rain between June and November and is primarily affected by the summer, or southwest, monsoon. The mountains affect the amount of rainfall deposited by the monsoons.
Windward areas receive heavy rains, whereas the leeward areas are considerably drier.
Typhoons are common. Native wildlife includes water buffalo, monkeys, reptiles, and tropical birds. There are substantial deposits of chromium, copper, gold, silver, manganese, lead, and iron ore and considerable hydroelectric power potential. Volcanic steam provides an increasing portion of the nation s power needs.