Tropical Cyclone Freddy is the longest-lasting tropical cyclone on record, enduring for 36 days, according to the World Meteorological Organization (WMO). Freddy crossed the Indian Ocean basin, starting off the coast of Northwest Australia and reached southern Africa in February and March 2023. The cyclone caused significant human and economic losses in the worst-affected countries.
An international committee of experts from the WMO’s Weather and Climate Extremes Archive conducted a thorough analysis and verification of Freddy’s distance and duration. The evaluation committee recognized Tropical Cyclone Freddy’s duration of 36 days at tropical storm status or higher as the new world record for the longest tropical cyclone duration.
PREVIOUS RECORD HOLDER
The previous record holder was Tropical Cyclone John, which existed in the North Pacific Ocean in 1994. Reanalysis indicated that it maintained tropical storm status or higher for 714 hours, or 29.75 days.
DISTANCE COVERED BY FREDDY
The WMO analysis indicated that Tropical Cyclone Freddy traveled 12,785 km ± 10 km (7,945 miles, 6,905 nautical miles) at tropical storm status or above. This distance is a close second to Tropical Cyclone John, which covered 13,159 km ± 10 km (8,177 miles, 7,105 nautical miles) at tropical storm status or above. To put that number in perspective, the distance Freddy covered is nearly 33% of the Earth’s circumference.
FREDDY’S IMPACT ON SOUTHEAST AFRICA
“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.
WMO’S CERTIFICATION PROCESS
“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,” said Randall Cerveny, Rapporteur of Climate and Weather Extremes for the WMO.
The WMO will update its Archive of Weather and Climate Extremes to reflect the new record. The archive includes records of the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum wind gust, longest lightning flash, and weather-related mortalities. It is an essential resource for weather historians and policy makers.
FUTURE EXTREME WEATHER EVENTS
“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.
Expert Committee and Global Collaboration
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) that forecasted TC Freddy, as well as scientists from Spain, Canada, Hong Kong China, and the United States.