There was no tropical cyclone activity in the Atlantic basin during June 1987.

These dates fall within the period with the most tropical cyclone activity in the Atlantic.

These dates encompass the vast majority of tropical cyclone activity in this region.

Towards the end of the season, tropical cyclone activity declined somewhat.

The measurement is a method to compare tropical cyclone activity between seasons.

Worldwide, tropical cyclone activity peaks in late summer when water temperatures are warmest.

Its area of responsibility covers more than 90% of the world's tropical cyclone activity.

This transition, the authors note, is largely responsible for the decreased hurricane and cyclone activity in 2009.

There was no tropical cyclone activity in the Atlantic basin during October 1986.

This is by far the most active basin, accounting for one-third of all tropical cyclone activity.