Due to harsh winds, frequent cloud cover, and cold temperatures, vegetation is mostly tundra (grasses, mosses, berries, low-lying flowering plants) at lower elevations.

Since the nearest U.S. military presence was in Cold Bay, Alaska, the U.S. began to construct bases in the western Aleutian Islands from which to launch operations against the Japanese.

Expecting a similar battle for Kiska Island, U.S. and Allied soldiers landing there August 15, 1943, found the occupiers had been stealthily evacuated by Japanese naval forces since the end of May, 1943.

After the war was over, the approximately 6,000 American military men who served on Adak during World War II recalled Adak's cold, foggy, windy weather; mud; Quonset huts; few women and no trees; and a volcano that from time to time would issue puffs of smoke.

The Alaska Department of Fish and Game introduced approximately 23 caribou calves to the island in the late 1950s, in part to help prevent famine emergencies.

[5][6] Adak Island, with its now large caribou herd of approximately 1,000 animals, according to a 2019 and 2022 count, has become a popular hunting destination.

[7][8] Adak has a subpolar oceanic climate (Koppen Cfc), characterized by persistently overcast skies, moderated temperatures, high winds, significant precipitation and frequent cyclonic storms.

[12] The Adak School, now closed due to declining enrollment, used to serves grades K–12 and had around 20 students before it was officially shuttered on June 30, 2023.

Alaskan-owned Norquest-Adak Seafood Co. processes Pacific cod, pollock, mackerel, halibut, albacore and brown king crab.

[15] Because of its naval aviation past, Adak has an unusually large and sophisticated airport for the Aleutian Islands.

Alaska Airlines operates twice-weekly Boeing 737-800 passenger and cargo jet service from Anchorage.

Adak Airport was historically served for many years by Reeve Aleutian Airways (RAA), with scheduled passenger flights to Anchorage operated with Lockheed L-188 Electra turboprop combi aircraft during the 1970s, followed by Boeing 727-100 jet combi aircraft during the 1980s and 1990s.

The city has requested funds to greatly expand the Sweeper Cove small boat harbor, including new breakwaters, a 315-foot (96 m) dock and new moorage floats [16] There are approximately 16 miles (26 km) of paved and primitive roads on Adak, all privately owned by the Aleut Corporation.