While the boundary of the terrestrial arctic regions can roughly be defined in relation to the Arctic Circle, permafrost or taiga to tundra passage, it is most commonly located at the Köppen line within which the temperature does not exceed 10 °C in the hottest month in July. The Arctic covers an area of 24 million km²: 17 million km2 of ocean, 3 million km² of lands and 4 million km² of islands. Victoria Island (Canadian Arctic Archipelago) covers an area of 217,291 km² and is located in the Northwest Passage.