The eighth typhoon of this year, Maria, hit Fujian province on July 11th. For Southerners at the coastal area, this is just the start of the typhoon season. However, whether you are a Southerner or a Northerner, how much do you know about typhoon, and could you tell the difference between a hurricane and a typhoon?

Hurricanes and typhoons are the same weather phenomenon: tropical cyclones. A tropical cyclone is a generic term used by meteorologists to describe a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has closed low-level circulation.

The weakest tropical cyclones are called tropical depressions. If a depression intensifies such that its maximum sustained winds reach 62 km per hour, the tropical cyclone becomes a tropical storm. Once a tropical cyclone reaches maximum sustained winds of 119 km per hour or higher, it is then classified as a hurricane, typhoon, or tropical cyclone, depending upon where the storm originates in the world. In the North Atlantic, central North Pacific, and eastern North Pacific, the term hurricane is used. The same type of disturbance in the Northwest Pacific is called a typhoon. Meanwhile, in the South Pacific and Indian Ocean, the generic term tropical cyclone is used, regardless of the strength of the wind associated with the weather system.

The ingredients for tropical cyclones include a pre-existing weather disturbance, warm tropical oceans, moisture, and relatively light winds. If the right conditions persist long enough, they can combine to produce the violent winds, incredible waves, torrential rains, and floods we associate with this phenomenon. At times, when a weather system does not meet all of these conditions, but is forecast to bring tropical storm or hurricane force winds to land in the next day or two, it is called a potential tropical cyclone in the Atlantic basin and the central and eastern North Pacific basins.

In the Northern Hemisphere, both hurricane season and typhoon season officially run from June 1 to November 30. Ninety-seven percent of tropical cyclone activity occurs during this time period. However, there is nothing magical about these dates. Hurricanes and typhoons can and do occur outside of this six month period.

In terms of name sources, typhoons and hurricanes differ in some ways. The list of typhoon names consists of entries from 17 Southeast and East Asian nations and the United States who have territories directly affected by typhoons. The submitted names are arranged into five lists, and each list is cycled with each year. Unlike tropical cyclones in other parts of the world, typhoons are not named after people. Instead, they generally refer to animals, flowers, astrological signs, and a few personal names.