Hurricane Wilma was the most intense tropical cyclone in the Atlantic basin and the second-most intense tropical cyclone in the Western Hemisphere, both based on barometric pressure, after Hurricane Patricia in 2015. Wilma's rapid intensification led to a 24-hour pressure drop of 97 mbar (2.9 inHg), setting a new basin record. At its peak, Hurricane Wilma's eye contracted to a record minimum diameter of 2.3 mi (3.7 km). In the record-breaking 2005 Atlantic hurricane season, Wilma was the twenty-second storm, thirteenth hurricane, sixth major hurricane, and fourth Category 5 hurricane, and was the second costliest hurricane in Mexican history, behind Hurricane Otis in 2023.
Its origins came from a tropical depression that formed in the Caribbean Sea near Jamaica on October 15, headed westward, and intensified into a tropical storm two days later, which abruptly turned southward and was named Wilma. Continuing to strengthen, Wilma eventually became a hurricane on October 18. Shortly thereafter, explosive intensification occurred, and in only 24 hours, Wilma became a Category 5 hurricane with wind speeds of 185 mph (295 km/h). Wilma's intensity slowly leveled off after becoming a Category 5 hurricane, and winds had decreased to 150 mph (240 km/h) before it reached the Yucatán Peninsula on October 20 and 21. After crossing the Yucatán, Wilma emerged into the Gulf of Mexico as a Category 2 hurricane. As it began accelerating to the northeast, gradual re-intensification occurred, and the hurricane was upgraded to Category 3 status on October 24. Shortly thereafter, Wilma made landfall in Cape Romano, Florida, with winds of 120 mph (190 km/h). As Wilma was crossing Florida, it briefly weakened back to a Category 2 hurricane, but again re-intensified as it reached the Atlantic Ocean. The hurricane intensified into a Category 3 hurricane for the last time, before weakening while accelerating northeastward. By October 26, Wilma transitioned into an extratropical cyclone southeast of Nova Scotia.
Early in Wilma's duration, flooding and landslides caused 12 deaths in Haiti and 1 death and about $93.5 million in damage in Jamaica. The Yucatán Peninsula experienced intense winds, torrential precipitation, and high storm surge. Wilma damaged 28,980 homes and 473 schools. The hurricane caused $4.6 billion in damage and eight deaths in Mexico. In Cuba, the storm damaged crops, roads, railways, 7,149 homes, 364 schools, and 3 hospitals. A total of 446 dwellings were destroyed. Damage throughout Cuba reached about $704 million. In Florida, strong winds impacted much of the southern portions of the state, while storm surge led to coastal flooding, especially in Collier and Monroe counties. The former, where the storm made landfall, suffered about $1.2 billion in damage, with 16,000 businesses and homes impacted to some degree. In the Miami metropolitan area, Palm Beach County reported damage to nearly 59,000 businesses and homes, while 5,111 residences in Broward County and at least 2,059 others in Miami-Dade County became uninhabitable. Approximately $19 billion in damage and 30 deaths occurred in Florida. Within the Bahamas, Wilma caused one death and damaged or destroyed hundreds of homes, mostly on Grand Bahama. Overall, at least 52 deaths were reported and damage totaled to $26.5 billion, most of which occurred in the United States.
In mid-October 2005, a large monsoon-like system developed in the Caribbean Sea. A broad low pressure area formed on October 13 to the southeast of Jamaica, which slowly became more defined while acquiring additional deep convection. On October 15 at 18:00 UTC, the National Hurricane Center (NHC) classified the system as Tropical Depression Twenty-Four while located about 220 mi (350 km) east-southeast of Grand Cayman. The depression drifted west-southwestward through a favorable environment, including warm sea surface temperatures, due to a high-pressure area over the Gulf of Mexico, a mid-tropospheric anticyclone to the east-northeast of the storm, and weak and poorly defined steering flow. The depression turned southwestward and strengthened into a tropical storm on October 17, whereupon the NHC designated it Wilma. Initial intensification was slow, due to Wilma's large size and a flat pressure gradient, although the associated convection gradually organized.
On October 18, Wilma curved west-northwestward and intensified into a hurricane, and subsequently underwent explosive deepening over the open waters of the Caribbean Sea. In a 30–hour period through October 19, Wilma's barometric pressure dropped from 982 to 882 millibars (29.0 to 26.0 inHg); this made Wilma the most intense Atlantic hurricane on record, based on pressure. During the same intensification period, the winds increased to a peak intensity of 185 mph (295 km/h), making Wilma a Category 5 on the Saffir–Simpson scale. An eyewall replacement cycle caused Wilma to weaken below Category 5 status on October 20. The storm then drifted northwestward toward Mexico's Yucatán Peninsula as a result of an increase in mid-level ridging to the northeast. Late on October 21, Wilma made landfall on the island of Cozumel, Quintana Roo, with sustained winds of 150 mph (240 km/h). About six hours later, 03:30 UTC the next day, Wilma made a second landfall on the Mexican mainland near Puerto Morelos, but with winds reduced to 135 mph (215 km/h).
The hurricane weakened over the Yucatán Peninsula to Category 2 intensity, but gradually re-strengthened once it reached the Gulf of Mexico, despite a significant increase in wind shear. Wilma re-intensified into a Category 3 hurricane early on October 24 as it accelerated to the northeast, steered by a powerful trough. After passing northwest of the Florida Keys, the hurricane struck southwestern Florida near Cape Romano around 10:30 UTC with winds of 120 mph (190 km/h). Wilma rapidly crossed the state and weakened to a Category 2 hurricane, emerging into the Atlantic Ocean near Jupiter. The cyclone briefly re-intensified to a Category 3 hurricane while passing north of the Bahamas later on October 24 while absorbing the smaller Tropical Storm Alpha to the east. The hurricane passed west of Bermuda on October 25. After cold air and wind shear penetrated the core of convection, Wilma transitioned into an extratropical cyclone on October 26 approximately 230 mi (370 km) southeast of Halifax, Nova Scotia, before it was absorbed by another extratropical storm a day later over Atlantic Canada.
At 08:01 UTC on October 19, a dropsonde from a hurricane hunter measured a barometric pressure of 884 mbar (26.1 inHg) in the eye of Wilma, along with sustained winds of 23 mph (37 km/h); the wind value suggested that the central pressure was slightly lower, estimated at 882 mbar (26.0 inHg). This is the lowest central pressure on record for any Atlantic hurricane, breaking the previous record of 888 mbar (26.2 inHg) set by Hurricane Gilbert in 1988; this value is also the tenth-lowest recorded worldwide officially. Wilma's intensification rate broke all records in the basin, with a 24–hour pressure drop of 97 mbar (2.9 inHg); this also broke the record set by Gilbert. At the hurricane's peak intensity, the Hurricane Hunters estimated the eye of Wilma contracted to a record minimum diameter of 2.3 mi (3.7 km).
While striking Mexico, it dropped torrential rainfall on the offshore Isla Mujeres. Over 24 hours, a rain gauge recorded 64.330 in (1,633.98 mm) of precipitation, which set a record in Mexico for the nation's highest 24–hour rainfall total, as well as the highest 24–hour rainfall total in the western hemisphere.
When Tropical Storm Wilma formed on October 17, it became the 21st named storm of 2005 season, which broke the record for most tropical cyclones in a single season, 20, set in 1933. An additional unnamed subtropical storm was added to 2005's tally after the season was over, making Wilma actually the 22nd storm of the season. With Wilma, an entire alphabetic 21-name list was fully used up for the first time, necessitating the naming of subsequent storms in that season by letters of the Greek alphabet. No season would again have 22 storms or make use of the Greek alphabet for storm names until 2020.