2004 Pacific typhoon season

The 2004 Pacific typhoon season was an extremely active season that featured the second-highest ACE ever recorded in a single season, second only to 1997, which featured 29 named storms, nineteen typhoons, and six super typhoons. It was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season ran throughout 2004, though most tropical cyclones typically develop between May and October. The season's first named storm and also the first typhoon, Sudal, developed on April 4, later was reached typhoon status two days later, and became the first super typhoon of the year three days later. The season's last named storm, Noru, dissipated on December 21.

The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones, which can often result in a cyclone having two names. The Japan Meteorological Agency (JMA) names a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least 65 km/h (40 mph) anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N and 25°N, regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center (JTWC) are given a number with a "W" suffix.