2005 Atlantic hurricane season statistics

Number of storms

The 2005 Atlantic hurricane season, with 28 nameable storms (wind speed ≥ 39 mph), is the most active season on record, surpassing the 1933 season's 20 nameable storms. With 15 hurricanes, the 2005 season also has had the most hurricanes formed, surpassing the 1969 season's 12. The season holds the record for the most major hurricanes, seven, tied the 1999 season's record of five Category 4 and 5 hurricanes and holds the record for the most Category 5 hurricanes in a single season, four (see below).

With the formation of Tropical Storm Vince, Tropical Storm Wilma, and Tropical Storm Alpha, 2005 became the first season to use the 'V', 'W' and Greek Letter names, respectively, since naming of Atlantic storms began in the 1950 season. It also has the distinction of being only the second season to use the 'R', 'S', and 'T' names. Only the 1995 season had previously used these letters.

2005 holds the record for the most storms to ever form during the month of July. Five storms (Cindy, Dennis, Emily, Franklin, and Gert) formed during that period. The previous record for most storms to form in the month of July was four; this record was held by the 1966 and 1995 seasons. The number of storms before the end of July (seven) is also a record, breaking the record of five set in the 1887, 1933, 1936, 1959, 1966, and 1995 seasons.

2005 and 1933 share the record for the most storms (17) forming before the end of September. The 2005 season now also holds the record for most storms (24) forming before the end of October (but not the record for within the month itself, the 1950 season had eight storms). 2005 also broke the record for most storms forming in November, with 3 storms (Gamma, Delta and Epsilon).

Total activity

Tropical activity during the 2005 season was unusually continuous from start to finish, unlike most hurricane seasons, which have significant quiet periods. Out of the 26 weeks in the hurricane season, just two had no tropical cyclones active at some point (the weeks of June 19 and November 6). For a 126-day stretch (June 28–October 31), only 16 didn't have a storm active and never more than three consecutive. There was record or near-record activity in every month of the season except for June. The 2005 season was the first time since reliable measurements began that the Atlantic basin recorded more tropical storms than the Western Pacific Ocean, which is typically the most active basin worldwide.

Statistics

This table gives the number of storms by month of formation and storm category on the Saffir-Simpson Hurricane Scale. The meanings of the one-letter (or number) categories can be ascertained by placing the cursor on that heading.

Entries which are bolded surpassed or tied records established by previous seasons.

Strongest storms

Hurricane Katrina was briefly the fourth most intense Atlantic hurricane on record, with a minimum central pressure of 902 mbar on August 28. It was surpassed by hurricanes Rita and Wilma later that season.

Hurricane Rita became the third most intense Atlantic hurricane and the most intense hurricane on record in the Gulf of Mexico after reaching a pressure of 895 mbar on September 21. It was surpassed by Wilma later in the season.

Hurricane Wilma became the most intense North Atlantic hurricane in recorded history shortly before 5:00 am EDT on October 18, when the central pressure was measured at 884 mbar. At 8:00 am EDT, Wilma continued to intensify, reaching 882 mbar. Wilma also holds the record of being the only storm recorded in the Atlantic basin to have a minimum central pressure below 900 mbar without also having Category 5 winds: on October 20 its winds were 155 mph and its central pressure was 894 mbar. Katrina, Rita and Wilma are the three most intense storms ever in a single Atlantic hurricane season.

2005 was the first time two storms recorded pressures below 900 millibars in a single season (Rita, 895; and Wilma, 882).

Hurricane Wilma also underwent the most rapid deepening for a 24-hour period ever measured. At noon on October 18, Wilma had a central pressure of 980 mbar (28.93 inches). At noon on October 19, Wilma had a central pressure of 882 mbar (26.04 inches), a pressure fall of 98 mbar (2.89 inches), breaking the previous record of 92 mbar (2.71 inches) set by Super Typhoon Forrest in the Western Pacific in 1983. Some sources, however, say that Forrest's pressure was lower than originally measured (876 mbar instead of 883 mbar). This would imply that Forrest retains the record with a pressure fall of 100 mbar in 24 hours, and thus this uncertainty is noted here.

In addition, Hurricane Dennis and Hurricane Emily, both in July, reached 930 mbar and 929 mbar respectively, becoming the two strongest storms on record in July.

Katrina was also the third most intense hurricane on record to make landfall in the United States in terms of pressure (920 mbar), behind the Labor Day Hurricane of 1935 and Hurricane Camille in 1969.

When Emily reached Category 5 intensity on July 16, it became the earliest Category 5 hurricane ever, shattering the record set by Hurricane Allen in the 1980 season. When Katrina reached Category 5 intensity on August 28, it became only the third time in recorded history (and the first time since the 1961 season) that there had been two Category 5 hurricanes in a single season. When Rita reached Category 5 intensity on September 21, 25 days after Katrina, the 2005 season became the first that had three Category 5 storms. When Wilma became a Category 5 storm on October 19, the 2005 season doubled the record set by the 1960 and 1961 seasons, becoming the first that had four Category 5 storms.

Rapid formation

Almost every storm in 2005 has set a record for early formation. The table shows the dates on which each storm formed, and the old record for earliest-forming storm of that number.

† Hurricane Dennis is now in third place; it was later surpassed by Tropical Storm Debby in 2012, which developed on June 23, and Tropical Storm Danielle in 2016, which developed on June 19.

Season effects

This is a table of all of the storms that formed in the 2005 Atlantic hurricane season. It includes their duration, names, damages, and death totals. Damage and deaths include totals while the storm was extratropical or a wave or low, and all of the damage figures are in 2005 USD.

Accumulated Cyclone Energy (ACE)

The table to the right shows the tropical storms of the 2005 season ranked from highest to lowest Accumulated Cyclone Energy (ACE), given to three significant figures. The total for the season was 248 x 10⁴ kt² which is the highest seasonal ACE value recorded. It is slightly higher than that for 1950 season which had an ACE of 243 x 10⁴ kt². ( the final storm of the season, Zeta, lasted into 2006. In calculating the seasonal ACE, the whole ACE of Zeta, including the contribution made in 2006, was used.)

ACE measures a combination of both the strength and duration of a tropical cyclone, so longer-lasting storms may accumulate more ACE than stronger storms with shorter durations. This discrepancy is most obvious in the comparatively high ACE value of Hurricane Emily to Hurricanes Katrina and Rita: Emily was not as strong as either storm, but formed out in the Atlantic and made a long track across the Caribbean Sea before making landfall. Katrina and Rita, however, both developed in the Bahamas, close to the U.S. mainland, and lasted for much shorter periods of time. In addition, Ophelia and Epsilon are high for their intensity because they maintained themselves for a long period of time and were slow to build and dissipate, as neither was ever more intense than a Category 1 storm.

The average ACE per storm in 2005 was actually close to the seasonal average. In comparison with previous seasons with high seasonal ACE values, relatively few strong, long-lasting storms, such as Cape Verde-type hurricanes, formed. Thus, although the number of named storms in 2005 was about 40% greater than that in any season since 1950, the seasonal ACE was only marginally greater than the previous record, set in 1950 itself, when the average ACE per storm was approximately double that of 2005.

Source: Best Track data from the Tropical Cyclone Reports.

Other records

Hurricane Vince developed in an unusual location in the northeastern Atlantic, well away from where tropical cyclones are usually found, though it is neither the most northerly-forming nor the most easterly-forming Atlantic tropical storm. It did, however, develop into a hurricane further east than any known storm, at 18.9° W. The National Hurricane Center declared that Vince was the first tropical cyclone on record to have made landfall on the Iberian Peninsula.

In the spring of 2006, the World Meteorological Organization retired five hurricane names: Dennis, Katrina, Rita, Stan, and Wilma. Their replacements in the 2011 season were Don, Katia, Rina, Sean, and Whitney, respectively. This surpassed the previous record for the number of hurricane names retired after a single season, four (held by the 1955, 1995, and 2004 seasons). The name Emily was not retired at the end of the season, making Hurricane Emily only the fourth Category 5 hurricane since 1953 to not have its name retired (Hurricane Dog of 1950 and Hurricane Easy of 1951 are omitted, as the phonetic alphabet was used from 1950–1952). The others were Hurricane Edith (1971), Hurricane Ethel (1960), and Hurricane Cleo (1958), although the name Cleo was retired in 1964 due to another storm. Due to reanalysis, it was determined that Ethel and Cleo did not peak as category 5 hurricanes, making Emily the second category 5 not to be retired, following Ethel.

Tropical Storm Zeta was one of only two Atlantic systems to exist in two calendar years (the other was Hurricane Alice in 1954-55). It was also one of four to exist in the month of January (the other three being Alice, Hurricane Alex of 2016, and a subtropical storm in 1978).