Which zones have the greatest and least annual variation in insolation? Why?

The zones on the Earth possessing the greatest and the least annual variation in insolation and the reason for the same.

The part of the Earth facing the Sun changes with time as it rotates and revolves. The axial tilt of the Earth along with the rotation and revolution may be the reason behind the difference in temperature experienced at different zones of the Earth.

Six latitudinal zones or bands of temperature and insolation encircling the Earth have been recognized as a whole; three zones each on both the hemispheres. The zone between the equator and the Tropic of Cancer is known as the north tropical zone. The corresponding zone in the Southern hemisphere lies between the Equator and Tropic of Capricorn and is known as the south tropical zone. These regions experience high insolation always however, is highest at noon when the sun is directly overhead. These regions experience almost equal amount of solar energy throughout the year and hence there is least annual seasonal variation of insolation.

The wide zone lying between the Tropic of Cancer and the Arctic Circle is known as the north middle latitude zone. The corresponding zone in the Southern hemisphere lies between the Tropic of Capricorn and Antarctic Circle and is known as the south middle latitude zone. In the north middle latitude zone, the insolation will be least during the December solstice, when the Sun is lowest in the sky and the day is the shortest...