List of off-season Atlantic hurricanes

An off-season Atlantic hurricane is a recorded tropical or subtropical cyclone that existed in the Atlantic basin outside of the official Atlantic hurricane season. The National Oceanic and Atmospheric Administration currently defines the season as occurring between June 1 and November 30 each calendar year, which is when 97% of all Atlantic tropical cyclones occur. Peak activity is known to be between August and October. In the off-season, storms are most likely to occur in May, with approximately 60% of such storms occurring during that month. Occasionally, however, storms develop in or persist until December. As of 2017, there have been 79 off-season cyclones in the Atlantic hurricane database, which began in 1851. In addition, there were six storms before 1851, and one hurricane in 1863 that is not part of the official database.

Off-season cyclones are most likely to occur in the central to western Atlantic Ocean, and most do not make landfall. Of the storms that did strike land, most affected areas surrounding the Caribbean Sea. Cumulatively, at least 398 deaths occurred due to the storms, primarily on the islands of Hispaniola and Cuba; a tropical storm in May 1948 struck the Dominican Republic to become the deadliest off-season storm. However, an unofficial hurricane in 1863 killed 110 people, in a shipwreck off Florida and on land. The same storm was estimated to have reached winds of 105 mph (165 km/h), making it the strongest hurricane between December to May; the strongest currently in the official database was a March hurricane in 1908 that reached winds of 100 mph (160 km/h). In addition, the strongest off-season cyclone to make landfall in the United States was Tropical Storm Beryl in 2012, which made landfall near Jacksonville Beach, Florida with 65 mph (100 km/h) winds. The most recent off-season storm was Tropical Storm Bonnie in May 2016.

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