During 1978, 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 110 systems formed, with 88 of these developing further and being named by the responsible warning centre. The strongest tropical cyclone of the year was Typhoon Rita, with a minimum barometric pressure of . The deadliest and costliest tropical cyclone of the year was the 1978 Sri Lanka cyclone that killed an estimated 915 people and caused $627 million in damages.

Compared to the previous year, 1978 formed less tropical cyclones. However, more of them were named than the previous year. The most active basin of the year was the Western Pacific which had 30 total storms that were named. Both the Eastern Pacific and Atlantic basins were above normal in activity, with 19 and 12 nameable storms forming respectively. The North Indian basin saw activity that was on par with the climatological norm. The southern hemisphere saw average numbers throughout each basin, being the South-West Indian Ocean, Australian region, and the South Pacific.

Tropical cyclone activity in each basin is under the authority of an RSMC. The National Hurricane Center (NHC) is responsible for tropical cyclones in the North Atlantic. The Eastern Pacific Hurricane Center (EPHC) is responsible for tropical cyclones in the Eastern Pacific.The Eastern Pacific Hurricane Center (EPHC) was the RSMC responsible for tracking tropical cyclones east of 140°W until the National Hurricane Center (NHC) took responsibility in the Spring of 1988. The Central Pacific Hurricane Center (CPHC) is responsible for tropical cyclones in the Central Pacific. The NHC, EPHC,The Eastern Pacific Hurricane Center (EPHC) was the RSMC responsible for tracking tropical cyclones east of 140°W until the National Hurricane Center (NHC) took responsibility in the Spring of 1988. and CPHC are subdivisions of the National Weather Service. Activity in the West Pacific is monitored by the Japan Meteorological Agency (JMA), at the time the Joint Typhoon Warning Center (JTWC) named tropical cyclones in the basin. Systems in the North Indian Ocean are monitored by the India Meteorological Department (IMD). The Météo-France located in Réunion (MFR) monitors tropical activity in the South-West Indian Ocean. The Australian region is monitored by five TCWCs that are under the coordination of the Australian Bureau of Meteorology (BOM). Similarly, the South Pacific is monitored by both the Fiji Meteorological Service (FMS) and the Meteorological Service of New Zealand Limited. Another, unofficial agency that provides additional guidance in tropical cyclone monitoring is the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Global atmospheric and hydrological conditions

Tropical cyclone climatology and variability throughout 1978 was dominated by a neutral El Niño Southern Oscillation (ENSO) that had emerged from a weakening Central Pacific-based El Niño event from the previous year, these neutral conditions persisted into the winter, and onto the next year.

Summary

North Atlantic Ocean

Atlantic hurricane season was slightly above average in terms of number of named storms. Eleven tropical cyclones were named in all, and five of these became hurricanes; two of the five became a major hurricane (Category 3 or higher on the Saffir–Simpson scale). This was also the last Atlantic hurricane season to use an all-female naming list. The season officially began on June 1, 1978, and ended on November 30, 1978. These dates, adopted by convention, denote the period in each year when most tropical cyclogenesis occurs in the Atlantic basin. However, the formation of subtropical or tropical cyclones is possible at any time of the year, as shown by the formation of an unnamed subtropical storm on January 18.

Three storms made landfall along the coast of the western Gulf of Mexico during the season. At the end of July and into early August, short-lived Tropical Storm Amelia and its remnants caused extensive flooding in Texas after dropping as much as of rain. There were 33 deaths and US$110 million (equivalent to $ million in ) in damage. Also in August, Tropical Storm Bess made landfall in Veracruz, and later, Tropical Storm Debra did so in Louisiana. Neither caused significant damage, though Debra or its remnants spawned multiple tornadoes that killed two people. Hurricanes Ella and Greta each reached Category 4 strength. Though remaining out at sea, Ella did lash the East Coast of the United States and Atlantic Canada with gusty winds and rip currents in early September. Greta brought strong winds, high tides, and flooding to Central America, particularly Belize and Honduras, resulting in about $25 million in damage and at least five fatalities. The storm crossed intact into the eastern Pacific Ocean and was renamed Olivia. Overall, the storms of this season collectively caused $141 million in damage and 42 fatalities.

Eastern & Central Pacific Ocean

This year’s Pacific hurricane season was the first Pacific hurricane season to use both masculine and feminine names for tropical cyclones. It also began the modern practice of utilizing naming lists every six years. Despite lacking an El Niño, a common driver of enhanced activity in the East and Central Pacific basins, the 1978 season was active. It featured 19 named storms, 14 hurricanes, and 7 major hurricanes, the latter of which are Category 3 or stronger cyclones on the Saffir–Simpson scale. Within the confines of the Central Pacific basin, located between the International Date Line and 140°W, 13 tropical cyclones or their remnants were observed by forecasters at the Central Pacific Hurricane Center, a record number of occurrences at the time. Seasonal activity began on May 30 and ended on October 21, within the limits of a traditional hurricane season which begins on May 15 in the East Pacific and June 1 in the Central Pacific. The season ends on November 30 in both basins. These dates conventionally delimit the period during each year when most tropical cyclones form.

The first system of the season, Aletta, made landfall on the Mexico coastline on May 31. Hurricanes Carlotta, Daniel, and Iva tracked into the Central Pacific as dissipating cyclones, where they produced a few inches of rainfall across the Hawaiian Islands. More substantive impacts came from Hurricane Fico, the longest-lived hurricane and the longest-tracked hurricane on record in the Central Pacific at the time. Large waves and rough seas caused severe damage to beachfront homes and forced the rescuing of stranded boaters offshore. Strong winds damaged trees and caused power outages. Damage across Hawaii totaled $200,000. In early September, the remnants of Hurricane Norman produced accumulating rain and snow across California, resulting in severe damage to its crops that totaled in excess of $300 million, in addition to killing eight people. In mid-October, Susan rapidly developed into a Category 4 hurricane over the Central Pacific, one of the strongest hurricanes on record there at the time. It persisted until October 21, marking an end to seasonal activity.

Western Pacific Ocean

The 1978 Pacific typhoon season was a very active season that produced 31 tropical storms, 16 typhoons and one intense typhoon. It ran year-round in 1978, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.

The first system formed on January 6, while the final system dissipated on December 19. The season's strongest storm was Typhoon Rita, which attained peak 1-minute sustained winds of 175 mph (280 km/h) and a minimum central pressure of 878 mbar (25.93 inHg). Rita was also the season's costliest and deadliest storm of the season, causing approximately US$100 million in damage and more than 300 fatalities, primarily across the Philippines. Other destructive storms included Typhoon Olive, which killed 66 people in the Philippines, Hong Kong, and Taiwan, and Typhoon Carmen, which caused US$3 million in damage and 21 deaths in the Ryukyu Islands, eastern China, and Korea. Overall, tropical cyclones during the season caused at least 1,374 deaths and more than US$760 million in damage.

North Indian Ocean

The 1978 North Indian Ocean cyclone season had no bounds, but tropical cyclones in the North Indian Ocean tend to form between April and December, with peaks in May and November. The 1978 season produced five cyclonic storms of which developed into three severe cyclonic storms. All five of the storms formed in the Bay of Bengal and four of those made landfall. The most notable storm of the season was BOB 11 which hit Sri Lanka.

South-West Indian Ocean January-June

The January-June portion of the 1977–78 South-West Indian Ocean cyclone season produced seven tropical cyclones between January and March 1978, of which five became named tropical storms and three intensified into tropical cyclones. Activity began on January 16 with the formation of Tropical Cyclone Fleur and concluded on March 19 with the dissipation of Tropical Storm Marylou. The strongest storm of the period was Tropical Cyclone Fleur, which attained peak 1-minute sustained winds of 125 mph (200 km/h) and a minimum central pressure of 941 mbar (27.79 inHg). Tropical Storm Kiki was the only system to cause fatalities, killing two people on Réunion, while no storm caused any reported monetary damage. Overall, tropical cyclones during the period caused two deaths and no reported damage.

July-December

The July-December portion of the 1978–79 South-West Indian Ocean cyclone season featured two tropical cyclones between July and December 1978, one of which became a named storm. Activity began on December 13 with the formation of Cyclone Angele which impacted Madagascar and Mozambique as a slow-moving major, followed up by Tropical Storm 03S which crossed over from the Australian region and dissipated on December 26.

Australian Region January–June

The January–June portion of the 1977–78 Australian region cyclone season was an above-average period that produced six tropical cyclones, of which all six became named storms and three intensified into severe tropical cyclones. Activity began on January 10 with the formation of Cyclone Trudy and concluded on April 11 with the crossover of Cyclone Hal into the South Pacific. The strongest storm during the period was Severe Tropical Cyclone Winnie, which attained peak 1-minute sustained winds of 125 mph (200 km/h) and a minimum central pressure of 945 mbar (27.91 inHg). The period's costliest storm was Cyclone Alby, which caused approximately US$45 million in damage and five fatalities after impacting Western Australia. Overall, tropical cyclones during the period caused at least seven deaths and approximately US$45 million in damage.

July–December

The July–December portion of the 1978–79 Australian region cyclone season produced three tropical cyclones, of which two became named storms and none intensified into a severe tropical cyclone. Activity began on November 19 with the formation of 01S and concluded on December 29 with the formation of Cyclone Peter, which remained active into January 1979. The strongest storm during the period was Cyclone Peter, which attained peak 1-minute sustained winds of 90 mph (145 km/h) and a minimum central pressure of 980 mbar (28.94 inHg). Peter was also the period's costliest and deadliest storm, causing approximately US$10 million in damage and two fatalities across Far North Queensland and Arnhem Land. Overall, tropical cyclones during the period caused two deaths and approximately US$10 million in damage.

South Pacific Ocean January–June