Tropical Cyclone

Several ocean areas adjacent to the equator possess all the necessary conditions for forming tropical cyclones. These spots are: the West Indies/Caribbean Sea where most hurricanes develop between August and November; the Pacific Ocean off the west coast of Mexico with a peak hurricane season of June through October; the western Pacific/South China Sea where most typhoons, baguios, and cyclones form between June and December; and south of the equator in the southern Indian Ocean and the south Pacific near Australia where the peak cyclone months are January to March. Note that in each area the peak season is during late summer (in the southern hemisphere summer runs from December to March). Tropical cyclones require warm surface waters at least 80°F (27°C). During the late summer months the sea surface temperatures reach their highest levels and provide tropical cyclones with the energy they need to develop into major storms.

The annual number of tropical cyclones reported varies widely between regions and from year to year. The West Indies recorded 658 tropical cyclones between 1886-1966, an average of about eight per year. Of these, 389, or about five per year, grew to be of hurricane strength. The Atlantic hurricane basin has a 50-year average of 10 tropical storms and six hurricanes annually.

In the United States, the National Weather Service names hurricanes from an alphabetic list of alternating male and female first names. New lists are drawn up each year to name the hurricanes of western Pacific and the West Indies. Other naming systems are used for the typhoons and cyclones of the eastern Pacific and Indian oceans.