The three heat zones are:

i. Torrid Zone- The mid-day sun is exactly overhead at least once a year on all latitudes in between the Tropic of Cancer and Tropic of Capricorn. This area therefore, receives maximum heat and is called the Torrid Zone.

ii. Temperate Zone- The mid-day sun never shines overhead on any latitude beyond the Tropic of Cancer and the Tropic of Capricorn. The angle of sun rays goes on decreasing towards the poles. As such, the areas bounded by the Tropic of Cancer and the Arctic Circle in the northern hemisphere and the Tropic of Capricorn and Antarctic Circle in the southern hemisphere have moderate temperatures. These are therefore, called temperate zones.

iii. Frigid Zone- Areas lying between the Arctic Circle and the North Pole in the Northern hemisphere and the Antarctic Circle and the South Pole in the Southern hemisphere are very cold. It is because here the sun does not rise much above the horizon. Therefore, its rays are always slanting and provide less heat. These are therefore, called Frigid zones.