The 2004 Atlantic hurricane season was an active North Atlantic tropical cyclone season when 24 named storms formed. The fatality numbers reached 571, the highest since 1999. The tropical cyclones in the season also caused major damages, accounting to $22 billion, the highest since 1992. Sea surface temperatures in 2004 were very high, causing increased activity. During August and September, 26 °C waters reached as far north as Newfoundland and the British Isles.
2004 was known by meteorologists as the 'Cape Verde year', stating that many of the storms in the season formed near Cape Verde. Hurricane Danielle was the most fatal this year, after killing 19 people in Jamaica and then 53 people in Mexico. There were two hurricanes that made landfall on the United States this year, Bonnie and Ivan.
The season was the most active Atlantic hurricane season on record, until it was taken over by 2005, which received 28 named storms. Nonetheless, 2004 set the record for the most hurricanes and most major hurricanes.
During 2004, the Atlantic Ocean was monitored officially by the National Hurricane Center (NHC), providing six-hourly updates on tropical cyclones.
The following names were used for named storms that formed in the Atlantic basin in 2004. The names not retired from this list will be used again in the 2010 season. This is the same list used for the 1998 season except for Gaston and Matthew, which replaced Georges and Mitch. Storms were named Gaston, Matthew, Otto, Paula, Richard, Shary, Tomas, Virginie and Walter for the first time in 2004. The Greek alphabet was also used for the first time this year.
In addition to the naming list above, three Greek alphabet names were used.
The World Meteorological Organization retired four names in the spring of 2005: Bonnie, Danielle and Gaston, Lisa and Tomas. They were replaced in 2010 by Bea, Daria, Libby and Tobias.