The 2017 Pacific typhoon season is an ongoing event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the western Pacific Ocean. The season runs throughout 2017, though most tropical cyclones typically develop between May and October. The season's first named storm, Muifa, developed on April 25. This season featured the latest occurrence of the first typhoon of the year since 1998, with Noru reaching this intensity on July 23.
The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and the 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) will name 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. PAGASA assigns unofficial names to tropical cyclones which move into or form as a tropical depression in their area of responsibility, located between 115°E–135°E and between 5°N–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 numerical designation with a "W" suffix.
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