During 2004, tropical cyclones formed within seven different tropical cyclone basins, located within various parts of the Atlantic, Pacific and Indian Oceans. During the year, a total of 132 systems formed with 82 of these developing further and were named by the responsible warning centre. The strongest tropical cyclone of the year was Cyclone Gafilo, which was estimated to have a minimum barometric pressure of . The most active basin in the year was the Western Pacific, which documented 29 named systems, while the North Atlantic 15 named systems formed. Conversely, both the Eastern Pacific hurricane and North Indian Ocean cyclone seasons experienced a below average number of named systems, numbering 12 and 4, respectively. Activity across the southern hemisphere's three basins—South-West Indian, Australian, and South Pacific—was spread evenly, with each region recording seven named storms apiece. Throughout the year, 28 Category 3 tropical cyclones formed, including seven Category 5 tropical cyclones formed in the year. The accumulated cyclone energy (ACE) index for the 2004 (seven basins combined), as calculated by Colorado State University was 1024.4 units.

The costliest tropical cyclone was Hurricane Ivan, which struck Caribbean and United States in September causing a tornado outbreak, with US$26.1 billion in damage. The deadliest tropical cyclone of the year was Hurricane Jeanne who killed for at least 3,006 deaths in Haiti.

Global atmospheric and hydrological conditions

Due to a Modoki El Niño – a rare type of El Niño in which unfavorable conditions are produced over the eastern Pacific instead of the Atlantic basin due to warmer sea surface temperatures farther west along the equatorial Pacific – activity was above average in North Atlantic Ocean.

Summary

North Atlantic Ocean It was an above average season in which 16 tropical cyclones formed. All but one tropical depression attained tropical storm status, and nine of these became hurricanes. Six hurricanes further intensified into major hurricanes.

Systems A total of 138 systems formed globally in the year with 60 of them causing significant damage, deaths, and/or setting records for their basin.

January

7 storms formed on January, in the Australian and Southwestern Indian basin, respectively. Cyclone Frank was the strongest. + Tropical cyclones formed in January 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsHetaDecember 25, 2003 – January 11, 200475 (45)992Western AustraliaNoneNoneKenJanuary 1–675 (45)992Western AustraliaNoneNoneMonsoon Depression January 10–17N/AN/AQueensland, New South WalesNoneNone05RJanuary 22–24UnspecifiedUnspecifiedNoneNoneNoneElitaJanuary 24–February 4120 (75)970Madagascar, Mozambique, Malawi, Seychelles, Mauritius, Réunion$287 Million33FrankJanuary 26–February 6185 (115)930RodriguesNoneNone08RJanuary 28UnspecifiedUnspecifiedNoneNoneNoneLindaJanuary 28–February 1 95 (60)985 NoneNoneNone

February

5 systems formed on February. 3 on Australian region, 1 on South Pacific basin, and 1 on the Western Pacific. Tropical Cyclone Ivy is the strongest. + Tropical cyclones formed in February 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsFritzFebruary 10–1595 (60)985Queensland, Northern TerritoryNoneNone01W (Ambo)February 11–1655 (35)1002Caroline IslandsNoneNoneIvyFebruary 21–28165 (105)935Vanuatu, Solomon Islands, New Caledonia, and New Zealand$3.8 million4MontyFebruary 25–March 3185 (115)935Western AustraliaMinorNoneEvanFebruary 27–March 465 (40)991Northern TerritoryNoneNone

March March was average, 12 storms formed during the month. Out of these, the strongest storm is Cyclone Gafilo with 895 hPa. Another storm that formed during the month, Hurricane Catarina, was a record-breaking storm that became the only hurricane in the South Atlantic.

+ Tropical cyclones formed in March 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsGafiloMarch 1–15230 (145)895Madagascar$250 million363Subtropical StormMarch 2–5UnspecifiedUnspecifiedNoneNoneNoneNicky-HelmaMarch 8–16110 (70)975 NoneNoneNoneFayMarch 12–28215 (130)910Northern Territory, Western AustraliaMinimalNone11RMarch 15–28UnspecifiedUnspecifiedNoneNone02W (Butchoy)March 18–2455 (35)1000PhilippinesNoneNoneGraceMarch 20–2395 (60)985NoneNoneNone06FMarch 20–22UnspecifiedUnspecifiedNoneNoneNoneOscar–ItsengMarch 21–29165 (105)940NoneNoneNoneCatarinaMarch 24–28155 (100)972 Santa Catarina, Rio Grande do Sul, Southern Brazil$350 million3–1108FMarch 28–April 1UnspecifiedUnspecifiedNoneNoneNone13RMarch 31–April 1UnspecifiedUnspecifiedNoneNoneNone

April Below average forming 9 systems. Only Typhoon Sudal became a storm, mostly being a depression.

+ Tropical cyclones formed in April 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths Refs09FApril 1–3UnspecifiedUnspecifiedNoneNoneNoneSudal (Cosme)April 4–15165 (105)940Caroline Islands$14 millionNone10FApril 4–955 (35)995 Fiji$4.17 million11 11FApril 7UnspecifiedUnspecifiedNoneNoneNone12FApril 7–13UnspecifiedUnspecifiedFijiNoneNone13FApril 12–13UnspecifiedUnspecifiedNoneNoneNone14FApril 18–19Unspecified1006 TongaNoneNone15FApril 21–24Unspecified1006 NoneNoneNone14RApril 26–27UnspecifiedUnspecifiedNoneNoneNone

May

8 systems formed on May. Typhoon Nida is the strongest. + Tropical cyclones formed in May 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsARB 01May 5–10100 (65)984Kochi$6.7 millionNoneJubaMay 5–17100 (65)980NoneNoneNoneNida (Dindo)May 13–21175 (115)935Caroline Islands, Philippines, Japan$1.3 million3105WMay 14–2055 (35)1004VietnamNoneNoneBOB 01May 16–19165 (105)952 Odisha, Bangladesh, Myanmar, Thailand, Yunnan$99.2 million236Omais (Enteng)May 16–2295 (60)985Caroline IslandsNoneNone16RMay 19–24UnspecifiedUnspecifiedNoneNoneNoneAgathaMay 22–2460 (95)997NoneNoneNone

June

7 storms formed on June. Typhoon Dianmu is the strongest. + Tropical cyclones formed in June 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsConson (Frank)June 4–11150 (90)960 Philippines, Taiwan, Japan$3.8 million 30Chanthu (Gener)June 5–15110 (70)975 Philippines, Vietnam, Cambodia, Laos, Thailand$7.9 million 39ARB 02June 10–1355 (35)992PuriNoneNoneBOB 02June 11–1455 (35)992 NoneNoneNoneDianmu (Helen)June 11–21185 (115)915Caroline Islands, Japan$68.5 million 6Mindulle (Igme)June 21–July 4175 (110)940Mariana Islands, Philippines, Taiwan, East China, Ryukyu Islands, Korea$833 million 56TingtingJune 25–July 4150 (90)955Caroline Islands, Mariana Islands$23.7 million 12

July

+ Tropical cyclones formed in July 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsTwo-EJuly 2–435 (55)1007 NoneNoneNoneOne-CJuly 5–630 (45)1007NoneNoneNoneBlasJuly 11–1565 (100)991 Northern MexicoNoneNoneKompasu (Julian)July 12–1685 (50)992 Philippines, Taiwan, South ChinaUnknownNoneCeliaJuly 19–2585 (140)981 NoneNoneNoneNamtheunJuly 24–August 3155 (100)955 JapanNoneNoneDarbyJuly 26–August 1120 (195)957 NoneMinimalNoneTDJuly 27Unspecified998 South ChinaNoneNoneAlex July 31–August 6120 (195)957 Southeastern United States, Atlantic Canada$7.5 million1

August

+ Tropical cyclones formed in August 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsSix-EAugust 1–230 (45)1008NoneNoneNoneBonnieAugust 3–14 65 (100)1001Lesser Antilles, Greater Antilles, Yucatán Peninsula, Southeastern United States (Florida), Mid-Atlantic states, New England, Atlantic Canada$1.27 million3 (1)MalouAugust 2–6 75 (45)996 JapanUnknownNoneMerantiAugust 2–9140 (85)960 Wake IslandNoneNoneRananim (Karen)August 6–15150 (90)950Ryukyu Islands, East China, Taiwan$2.44 billion 169TDAugust 6–7Unspecified1002 NoneNoneNoneTDAugust 7–8Unspecified1002 NoneNoneNoneMalakasAugust 9–1385 (50)990 NoneUnknown NoneCharleyAugust 9–14150 (240)941Lesser Antilles, Greater Antilles (Cuba), East Coast of the United States (Florida)$16.9 billion 15 (20)DanielleAugust 13–21 110 (175)964Cape VerdeNoneNoneEarl August 13–15 50 (85)1009Windward IslandsNone1Megi (Lawin)August 14–20 120 (75)970 Japan, KoreaUnknown5ChabaAugust 17–31205 (125)910 Ryukyu Islands, South Korea, Japan$977 million20 Aere (Marce)August 18–31 150 (90)955 Caroline Islands, Ryukyu Islands, China, Taiwan $313 thousand107EstelleAugust 19–2470 (110)989NoneNoneNoneFrankAugust 23–2670 (110)979Baja California PeninsulaNoneNoneNine-EAugust 23–2635 (55)1005NoneNoneNoneFrancesAugust 24–September 7145 (230)935(The Bahamas), Southern United States, Midwestern United States, Mid-Atlantic states, New England, Atlantic Canada$10.1 billion7 (42) 21WAugust 25–3155 (35)1000 Mariana IslandsNoneNoneGeorgetteAugust 26–3065 (100)995NoneNoneNoneSongda (Nina)August 26–September 8175 (110)925 Marshall Islands, Mariana Islands, Japan, South Korea $9 billion28 GastonAugust 27–September 175 (120)985The Carolinas (South Carolina), Mid-Atlantic states, New England, Atlantic Canada$130 million8 (1) HermineAugust 27–3060 (95)1002New England (Massachusetts), Atlantic CanadaMinimalNoneHowardAugust 30–September 5140 (220)943Baja California Peninsula, Western United States MinimalNone

September

+ Tropical cyclones formed in September 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsPhoebeSeptember 1–585 (50)990NoneNoneNoneIvanSeptember 2–24270 (165)910Lesser Antilles, Venezuela, Greater Antilles, Gulf Coast of the United States (Alabama, Louisiana), Eastern United States, Atlantic Canada$26.1 billion94 (33) SarikaSeptember 3–9 100 (65)980 Mariana IslandsNone None TenSeptember 7–9 35 (55)1009NoneNoneNoneTDSeptember 8–11 Not specified 1002Ryukyu IslandsNone None IsisSeptember 8–16 75 (120)987NoneNoneNoneJavierSeptember 10–19 150 (240)930 Baja California, Southwestern United StatesNoneNoneHaima (Ofel)September 10–1375 (45)996 Taiwan, East China$7.64 millionNone TDSeptember 12Unspecified 1008 TaiwanNoneNoneBOB 03September 12–1545 (30)996 West BengalNone33JeanneSeptember 13–28195 (120)950 Leeward Islands (Guadeloupe), Greater Antilles (Puerto Rico, Dominican Republic), (The Bahamas), Southeastern United States (Florida), Mid-Atlantic states, New England, Atlantic Canada$7.94 billion 3,042 PabloSeptember 15–20Unspecified1008 Philippines, VietnamNoneNoneTDSeptember 15–16Unspecified1006 East ChinaNoneNoneKarlSeptember 16–24145 (230)938Faroe Islands, Iceland, NorwayMinimalNoneLisaSeptember 19–October 375 (120)987NoneNoneNoneMeari (Quinta)September 19–September 29165 (105)940 Caroline Islands, Japan $798 million 18TDSeptember 20Unspecified1008 NoneNoneNoneOnilSeptember 30–October 3100 (65)990 India, PakistanNone9

October

+ Tropical cyclones formed in October 2004 Storm name Dates active Max windkm/h (mph) Pressure(hPa) Areas affected Damage(USD) Deaths RefsBOB 04/05October 2–845 (30)1002India$23.9 million218 Ma-on (Rolly)October 3–10185 (115)920Japan$603 millionUnknownKayOctober 4–645 (75)1004NoneNoneNoneMatthewOctober 8–1045 (75)997Gulf Coast of the United States (Louisiana), Midwestern United States, Great Plains$305 thousandNoneTDOctober 9–13Unspecified1004 NoneNoneNoneNicoleOctober 10–1150 (85)986Bermuda, Maine, Atlantic Canada NoneNoneTokage (Siony)October 10–20155 (100)940Mariana Islands, Taiwan, Japan$3.23 billion95LesterOctober 11–1350 (85)1000Southwestern MexicoNoneNoneNock-ten (Tonyo)October 14–26155 (100)945Caroline Islands, Mariana Islands, Taiwan, Ryukyu Islands None302October 25–29UnspecifiedUnspecifiedNoneNoneNoneSixteen-EOctober 25–2635 (55)1004Northern MexicoNoneNone01FOctober 28–3045 (30)1001 NoneNoneNone

November