During 2016, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, 140 tropical cyclones formed in bodies of water known as tropical cyclone basins. Of these, 84, including two subtropical cyclones in the South Atlantic Ocean and two tropical-like cyclones in the Mediterranean, were named by various weather agencies when they attained maximum sustained winds of . The strongest storm of the year was Winston, peaking with a pressure of and with 10-minute sustained winds of before striking Fiji. The costliest and deadliest tropical cyclone in 2016 was Hurricane Matthew, which impacted Haiti, Cuba, Florida, Georgia and the Carolinas, causing US$15.09 billion in damage. Matthew killed 603 people; 546 in Haiti, 47 in United States, 4 in Cuba and Dominican Republic, and 1 in Colombia and St. Vincent.
2016 had a slightly above average amount of tropical cyclones forming in the year. The most active basin of the year was the Western Pacific documenting a record 26 named storms. The Eastern Pacific also had an above-average season with 21 named storms forming. The North Atlantic similarly was the first above-average since 2012 with 15 named storms and 7 hurricanes forming. The above activity can be blamed on a La Niña pattern which formed during the summer of the year. In the North Indian Ocean was a relatively below-average season which featured four named storms. The Southern Hemisphere had relatively average activity throughout much of the year– with the exception of the Australian region which remained below average because of positive IOD– the other South-West Indian Ocean and South Pacific basins featured above-average seasons. Eight Category 5 tropical cyclones were formed in 2016.
Tropical cyclones are primarily monitored by a group of ten warning centers, which have been designated as a Regional Specialized Meteorological Centre (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 Indian Meteorological Department (IMD), Météo-France (MFR), 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 centers include the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA), the United States Joint Typhoon Warning Center (JTWC), and the Brazilian Navy Hydrographic Center(BNHC).
Global atmospheric and hydrological conditions
During November and December 2015, values within NOAA's Oceanic Niño Index peaked at , which surpassed December 1997 value of . NOAA subsequently reported that the 3-month average from November 2015 to January 2016 of the ONI had peaked at , which meant that the 2014–16 event was tied with the 1997–98 event for the strongest values on record. However, overall the event was considered to be one of the three strongest El Nino events since 1950, since there was a number of different ways to measure the strength of an event. The event subsequently started to weaken with sea surface temperature anomalies across the equatorial pacific decreasing, while predictions about a possible La Niña event taking place during 2016 started to be made.
During May 2016, the El Niño event dissipated as near to below average sea surface temperatures, expanded across the eastern equatorial Pacific Ocean. Atmospheric anomalies over the tropical Pacific Ocean had also weakened and become consistent with ENSO neutral conditions. These anomalies included the traditional and equatorial Southern Oscillation indices becoming near zero, while atmospheric convection, upper and lower level winds all became near average. As a result of this the BoM, NOAA's CPC, IRI, and the JMA, all declared that the record-tying El Niño event had ended in late May/early June.