Cyclone Freddy Declared Longest-Lasting Tropical Cyclone on Record by WMO

A satellite image of Tropical Cyclone Freddy over the Indian Ocean displayed distinct cloud formations and colorful atmospheric patterns, with partial views of surrounding coastlines.

The World Meteorological Organization (WMO) has officially declared Tropical Cyclone Freddy as the longest-lasting tropical cyclone on record, lasting 36 days. Freddy, which traversed the Indian Ocean, began off the coast of Northwest Australia and reached southern Africa during February and March 2023, causing significant human and economic losses in the worst-affected countries.

A satellite image of Tropical Cyclone Freddy over the Indian Ocean displayed distinct cloud formations and colorful atmospheric patterns, with partial views of surrounding coastlines.

An international committee of experts under the auspices of the WMO Weather and Climate Extremes Archive conducted a detailed analysis and verification of the cyclone's distance and duration. This evaluation committee confirmed that Tropical Cyclone (TC) Freddy’s duration of 36.0 days at tropical storm status or higher sets a new world record for the longest tropical cyclone duration.

Previous Record

The previous record holder, TC John, existed in the North Pacific Ocean in 1994 at tropical storm status or higher for a combined duration of 714 hours, or 29.75 days. A reanalysis of TC John's duration reaffirmed this duration but fell short of Freddy's longevity.

Distance Covered

In terms of distance, the WMO analysis indicated that TC Freddy traveled 12,785 km ± 10 km (7,945 miles, 6,905 nautical miles) at tropical storm status or above. This distance places Freddy second only to TC John, which covered 13,159 km ± 10 km (8,177 miles, 7,105 nautical miles). For perspective, Freddy’s distance is nearly 33% of the Earth’s circumference.

Expert Opinions

“Freddy was a remarkable tropical cyclone, not only for its longevity but also for its ability to survive multiple land interactions, which unfortunately had significant consequences for southeast African populations," said Chris Velden, a committee member and tropical cyclone/satellite expert from the University of Wisconsin, USA.

“This investigation highlights the meticulous care that the WMO undertakes in certifying all weather observations. Such painstaking evaluation provides the critical confidence that our global records of all weather phenomena are properly measured,” added Randall Cerveny, Rapporteur of Climate and Weather Extremes for WMO.

WMO Archive Update

WMO will update its Archive of Weather and Climate Extremes to reflect this new record. The archive includes records for the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, longest lightning flash, and weather-related mortalities. This archive is a crucial resource for weather historians and policy makers.

“The extremes presented for adjudication for the WMO Weather and Climate Extremes Archive are ‘snapshots’ of our current climate. It is possible, and indeed likely, that greater extremes will occur in the future. When such observations are made, new WMO evaluation committees will be formed to adjudicate these observations,” said Randall Cerveny.

Evaluation Committee

The WMO evaluation committee consisted of experts from the Tropical Cyclone Warning Center Melbourne (Bureau of Meteorology, Australia), the Regional Specialized Meteorological Centre (RSMC) La Réunion (Météo-France, France), which forecasted TC Freddy, as well as scientists from Spain, Canada, Hong Kong China, and the United States.

Tropical Cyclone Freddy’s record-breaking longevity and extensive journey across the Indian Ocean underscore the importance of meticulous weather observation and the potential for future extreme weather events.