The climate of Arunachal Pradesh varies with elevation. Areas with very high elevation in the Upper Himalayas near the Tibetan border enjoy an alpine or Tundra climate.

Below the Upper Himalayas come the Middle Himalayas, where people experience a temperate climate. Fruits like apples, oranges, etc are grown. Areas at the sub-Himalayan and sea-level elevation experience a humid sub-tropical climate, with hot summers and mild winters.

The state receives heavy rainfall of 80 to 160 inches (2,000 to 4,000 mm) annually, most of it falling between May and September. The mountain slopes and hills are covered with alpine, temperate, and subtropical forests of dwarf rhododendron, oak, pine, maple, fir, and juniper; sal (Shorea) and teak are the main economic species.