An off-season Atlantic hurricane is a 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.[1] Peak activity is known to be between August and October.[1][2] Between 1938, when the United States Weather Bureau began issuing tropical cyclone warnings as a collaborative observation network for cities along the U.S. coastline, and 1963, the season was defined between June 15 and November 15.[3] In 1964, the season was extended to begin on June 1 and end on November 30,[2] which remains the official length of the season.
As of 2023[update], there have been 92 off-season cyclones recorded in the official Atlantic hurricane database, which dates back to 1851. In addition, six earlier such storms have been documented, but are not part of the database. The first off-season storm in the database was an 1865 storm that developed in the Caribbean Sea; an earlier documented 1863 hurricane is not part of the database. The most recent off-season system was an unnamed January subtropical storm in 2023.
- ^ a b Dorst, Neil; Hurricane Research Division; Atlantic Oceanographic and Meteorological Laboratory (2012). "Subject: G1 – When is hurricane season?". United States National Oceanic and Atmospheric Administration's Office of Oceanic and Atmospheric Research. Retrieved 2010-03-02.
- ^ a b Staff writer (1964-06-01). "Annual Man Against Nature Battle Opens This Morning". Sarasota Herald-Tribune. United Press International. p. 2. Retrieved 2010-02-28.
- ^ Staff writer (1938-06-15). "Hurricane Warning Service Expanded". The Evening Independent. Associated Press. p. 14. Retrieved 2010-02-28.