The 2005 Atlantic hurricane season was a record-breaking, devastating and deadly Atlantic hurricane season. It is the second-costliest hurricane season, just behind the 2017 season. It featured 28 tropical and subtropical storms, which was the most recorded in a hurricane season until the 2020 season. The United States National Hurricane Center named 27 storms, exhausting the annual pre-designated list, requiring the use of six Greek letter names, and adding an additional unnamed subtropical storm during a post-season re-analysis. A record 15 storms attained hurricane status, with maximum sustained winds of at least 74 miles per hour (119 km/h). Of those, a record seven became major hurricanes, rated Category 3 or higher on the Saffir–Simpson scale. Four storms of this season became Category 5 hurricanes, the most of any season on record.
The four Category 5 hurricanes during the season were: Emily, Katrina, Rita, and Wilma. In July, Emily reached peak intensity in the Caribbean Sea, becoming the first Category 5 hurricane of the season, later weakening and striking Mexico twice. It was the first Category 5 hurricane recorded in the month of July and was the earliest-forming Category 5 hurricane on record, until Hurricane Beryl surpassed the record in July 2024. In August, Katrina reached peak winds in the Gulf of Mexico but weakened by the time it struck the U.S. states of Louisiana and Mississippi. The most devastating effects of the season were felt on the Gulf Coast of the United States, where Katrina's storm surge crippled New Orleans, Louisiana, for weeks and devastated the Mississippi coastline. Katrina became the costliest U.S. hurricane, leaving $125 billion in damage and 1,392 deaths. Rita followed in September, reaching peak intensity in the Gulf of Mexico before weakening and hitting near the border of Texas and Louisiana. The season's strongest hurricane, Wilma, became the most intense Atlantic hurricane on record, as measured by barometric pressure. Lasting for ten days in October, Wilma moved over Cozumel, the Yucatán Peninsula, and Florida, causing over $22 billion in damage and 52 deaths.