2004 WMHB Pacific typhoon season

The 2004 Pacific typhoon season was an extremely active Pacific typhoon season. With 33 named storms, 24 typhoons, and 10 super typhoons forming, it was the most active season since 1994. The season officially began on January 1, 2004, and ended on December 31, 2004. These dates historically describe the period each year when most tropical cyclones form in the Northwest Pacific basin and are adopted by convention. The season's first tropical cyclone, Tropical Storm Chaba, developed on February 11.

Storm names
Within the Northwest Pacific Ocean, both the Japan Meteorological Agency (JMA) and the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assign names to tropical cyclones that develop in the Western Pacific, which can result in a tropical cyclone having two names. The Japan Meteorological Agency's RSMC Tokyo — Typhoon Center assigns international names to tropical cyclones on behalf of the World Meteorological Organization's Typhoon Committee, should they be judged to have 10-minute sustained windspeeds of 65 km/h (40 mph). PAGASA assigns names to tropical cyclones which move into or develop as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N and 25°N even if the cyclone has had an international name assigned to it. The names of significant tropical cyclones are retired, by both PAGASA and the Typhoon Committee. Should the list of names for the Philippine region be exhausted then names will be taken from an auxiliary list of which the first ten are published each season.

Retirement
In the fall of 2005, at the 38th session of the ESCAP/WMO Typhoon Committee, the World Meteorological Organization retired the names Songda, Muifa, Roke, and Haitang from its rotating name lists due to the amount of damage and deaths they caused, and they will not be used again for another Pacific typhoon. They were replaced with ???, ???, Koto, Fengling, and ???.