The climate of the Alaska Peninsula and Katmai National Park and Preserve is influenced by storms originating in the North Pacific and moving along a storm track that parallels the Aleutian chain. Storm frequency is greatest between August and October, but local geographic conditions produce a variety of microclimates. High winds are common along the Shelikof Strait due to the funneling of air between Kodiak Island and the Aleutian Range. The Aleutian Range also forms a cloud barrier, creating orographic rainfall along the Shelikof coast and on the eastern flank of the Aleutian Range.
Katmai rests above a convergent plate margin, part of the circum-Pacific Ring of Fire, and one of the most active volcanic belts in the world. The 1912 eruption of Novarupta and subsequent caldera-forming collapse of Mt. Katmai are the most significant volcanic events occurring in historic times. Ash from Novarupta covered the adjacent valley to great depth, creating numerous fumaroles and thus the name, the Valley of Ten Thousand Smokes. Mt. Trident erupted in 1952, and minor ash eruptions and outbursts have also occurred on Mount Mageik, Mount Martin, Novarupta, and Mt. Katmai since the 1912 eruption.