The 2004 North Indian Ocean cyclone season was the first in which tropical cyclones were officially named in the basin. Cyclone Onil, which struck India and Pakistan, was named in late September. The final storm, Cyclone Agni, was also named, and crossed into the southern hemisphere shortly before dissipation. This storm became notable during its origins and became one of the storms closest to the equator. The season was fairly active, with ten depressions forming from May to November. The India Meteorological Department designated four of these as cyclonic storms, which have maximum sustained winds of at least 65 km/h (40 mph) averaged over three minutes. The Joint Typhoon Warning Center also issued warnings for five of the storms on an unofficial basis.

The 2004 Atlantic hurricane season was a very deadly, destructive, and active Atlantic hurricane season, with over 3,200 deaths and more than $61 billion in damage. More than half of the 16 tropical cyclones brushed or struck the United States. Due to the development of 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. The season officially began on June 1 and ended on November 30, though the season's last storm, Otto, dissipated on December 3, extending the season beyond its traditional boundaries. The first storm, Alex, developed offshore of the Southeastern United States on July 31, one of the latest dates on record to see the formation of the first system in an Atlantic hurricane season. It brushed the Carolinas and the Mid-Atlantic, causing one death and $7.5 million (2004 USD) in damage. Several storms caused only minor damage, including tropical storms Bonnie, Earl, Hermine, and Matthew. In addition, hurricanes Danielle, Karl, and Lisa, Tropical Depression Ten, Subtropical Storm Nicole and Tropical Storm Otto had no effect on land while tropical cyclones. The season was the first to exceed 200 units in accumulated cyclone energy (ACE) since 1995, mostly from Hurricane Ivan, the storm produced the highest ACE. Ivan generated the second-highest ACE in the Atlantic, only behind 1899 San Ciriaco Hurricane.