There are six regions of tropical cyclones all of which are found on the tropical or subtropical seas:-
(1) Tropical North Atlantic-West Indies, Gulf of Mexico and Caribbean Sea.
(2) Western part of the tropical North Pacific-the Philippines, the China Sea and areas around Japan.
(3) Eastern part of the tropical North Pacific-the western coastal areas of Mexico and Central America.
(4) The Bay of Bengal and the Arabian Sea.
(5) The South Indian Ocean – west of Tuamotu Islands and the Coral Sea, in the region of Samoa and Fiji Islands and the east coast of Australia.
Tropical cyclones are completely absent in the tropical areas of the south Atlantic and the eastern South Pacific east of 140° West longitude.
Tropical cyclones do not develop over land, although they often move far into the margins of continents.
The largest number of tropical storms develops in the southern segment of the North Pacific Ocean. Besides, the western part of the tropical North Atlantic and the Caribbean Sea region are visited by the most destructive type of hurricanes.
The tropical cyclone activity is at its maximum in late summer and early autumn. It may be pointed out that the highest frequency of tropical storms is recorded during the period of highest ocean surface temperature.
This period also coincides with the time of maximum pole-ward displacement of the inter-tropical convergence zone.