4.12% of Earth's surface.
# The North Temperate Zone, between the Arctic Circle at N and the Tropic of Cancer at N, covers 25.99% of Earth's surface.
# The Torrid Zone, between the Tropic of Cancer at N and the Tropic of Capricorn at S, covers 39.78% of Earth's surface.
# The South Temperate Zone, between the Tropic