Tropical cyclones in 2009

Throughout 2009, 130 tropical cyclones formed in bodies of water known as tropical cyclone basins. Of these, 81 were named, including a subtropical cyclone in the South Atlantic Ocean, by various weather agencies when they attained maximum sustained winds of 35 knots (65 km/h; 40 mph). The strongest storm of the year was Typhoon Nida in the Western Pacific Ocean. The deadliest and costliest storm of the year was Typhoon Morakot (Kiko) causing 789 fatalities through its track in the Philippines, Japan, Taiwan, China, and the Korean peninsula. Throughout the year, twenty-one Category 3 tropical cyclones formed, including five Category 5 tropical cyclones in the year. The accumulated cyclone energy (ACE) index for the 2009 (seven basins combined), as calculated by Colorado State University was 609.6 units.

Tropical cyclones are primarily monitored by a group of ten warning centres, which have been designated as a Regional Specialized Meteorological Center (RSMC) or a Tropical Cyclone Warning Center (TCWC) by the World Meteorological Organization. These are the United States National Hurricane Center (NHC) and Central Pacific Hurricane Center, the Japan Meteorological Agency (JMA), the India Meteorological Department (IMD), Météo-France, Indonesia's Badan Meteorologi, Klimatologi, dan Geofisika, the Australian Bureau of Meteorology (BOM), Papua New Guinea's National Weather Service, the Fiji Meteorological Service (FMS) as well as New Zealand's MetService. Other notable warning centres include the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), the United States Joint Typhoon Warning Center (JTWC), and the Brazilian Navy Hydrographic Center.