The 1983 Pacific hurricane season was an above average Pacific hurricane season which became the longest season ever recorded at the time. The season began on May 15, 1983 in the eastern Pacific, and on June 1, 1983 in the central Pacific, and ended on November 30, 1983. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean. During the 1983 season, there were 20 named storms, which was slightly less than the previous season. Furthermore, twelve storms strengthened into hurricanes while eight reached major hurricane status, Category 3 or higher on the Saffir–Simpson hurricane wind scale (SSHWS). The decaying 1982–83 El Niño event likely contributed to a high level of activity. That same El Niño influenced a very quiet Atlantic hurricane season.

The first storm of the season, Hurricane Adolph, became the southernmost-forming east Pacific tropical cyclone on record after forming at a latitude of 7.1°N. After a slow start, activity picked up in July, when Hurricane Gil moved through the Hawaiian Islands, resulting in minor damage. In early August, Hurricane Ismael was responsible for three deaths and $19 million (1983 USD) in damage in the United States. In September, hurricanes Kiko and Lorena brought significant damage and seven deaths to southern Mexico. About a month later, Tropical Storm Octave became the worst tropical cyclone on record to affect Arizona. Octave killed 15 people, and caused $500 million in damage to Arizona and $12.5 million to New Mexico. Later in October, Hurricane Tico was a very intense hurricane at the time of its landfall and thus left 25,000 homeless. Damage throughout the country was estimated at $200 million while 135 deaths were reported in Mexico. Although the majority of its impact occurred in Mexico, Tico's remnants brought significant flooding in the Central United States, resulting in six deaths and $42 million in damage. A few days later, Hurricane Raymond posed a threat to Hawaii, but sustained minimal damage. The final storm of the season, Hurricane Winnie, was a rare December cyclone.

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Seasonal summary

During the 1983 season, a total of 21 named storms formed, which was well-above the long-term average of 15. However, this total was slightly less active than the 1982 Pacific hurricane season, which saw a then-record 22 storms form. However, 1983 was at that time the most active season in the Eastern Pacific Hurricane Center (EPHC) warning zone, but this record itself was surpassed during the 1985 Pacific hurricane season, and again in the 1992 Pacific hurricane season. Additionally, 12 storms reached hurricane intensity, which was above the average of eight. Of the 12 hurricanes, eight attained Category 3 intensity or higher on the SSHWS. The season started on May 21 with the formation of Adolph and ended on December 9, with the dissipation of Hurricane Winnie. Lasting 201 days, 1983 was the longest season on record. There were a total of 1,238 storm hours, which was the most in four years. Despite the activity in the EPHC's warning responsibility, only two storms formed in the Central Pacific Hurricane Center (CPHC)'s area of responsibility, both of which stayed depressions. A moderate El Niño was present throughout the season, with water temperatures across the equatorial Central Pacific was nearly 5 °F (0.6 °C) above normal. The Pacific decadal oscillation (PDO) was in a warm phase during this time period. Both of these factors are known to enhance Pacific hurricane season activity. Furthermore, 1983 was in the middle of an era where all but the 1988 Pacific hurricane season was near or above average.

One storm in 1983 formed in May, an event the occurs every other year on average. Another storm formed in June, which was below the average of 1.7 storms per June. Despite a somewhat slow start, activity picked up in July, where 6 storms formed. This was twice the average, though only two of the storms thus far had exceeded hurricane intensity. Although August was less active, with only 3 storms developing, compared to the average of 4, two of the storms that formed in July lasted into the early part of the month. However, activity picked back up again in September, with 5 storms forming, which was above the average of 3. Three storms also formed in October, which was two storms above normal. One storm developed in November as well, a somewhat unusual occurrence. For the first time since 1947, a hurricane developed in December.

Three storms during the season made landfall on Mexico. The first, Adolph did so in May. The second, Tico, hit near Mazatlán as a powerful hurricane, resulting in severe damage. Around this time, a weak tropical depression made landfall along the western portion of the nation as well. In addition, Tropical Depression Raymond made landfall on Hawaii in late October. Hurricane Hunters flew into 2 storms within the EPHC zone, Manuel and Ismael. Moreover, they flew into 3 storms in CPHC's area of responsibility, Tropical Storms Gil and Narda, and Hurricane Raymond.

Systems Hurricane Adolph

On May 21, a tropical depression formed southwest of Managua, at a latitude of 7.1°N, becoming the southernmost-forming tropical cyclone in the east Pacific basin. As the depression headed gradually west-northwestward over extremely warm sea surface temperatures, it steadily intensified. Later that day, the depression intensified into Tropical Storm Adolph. Further intensification occurred as Adolph headed west-northwestward; by May 24, the EPHC reported that Adolph had strengthened into a hurricane, setting a then-record for the earliest known hurricane in the basin, though this was later surpassed by Hurricane Alma in May 1990. Shortly thereafter, the storm turned northwestward and intensified into a Category 2 hurricane on the SSHWS. Around that time, Adolph attained its peak intensity with winds of . At that time, Adolph was the strongest May hurricane on record. However, this record was broken by a hurricane of the same name in 2001.

Following peak intensity, Adolph gradually weakened to a Category 1 hurricane. By May 25, Adolph curved sharply north-northeastward, as a result of being steered by anticyclonic deep-layer mean. Despite being situated over fairly warm waters, Adolph weakened considerably due to increased wind shear. Although the EPHC expected the storm to stay at sea, Adolph curved north-northeastward. It was then downgraded to a tropical storm on May 25. Rapidly weakening, Tropical Storm Adolph moved onshore near Puerto Vallarta early the next day. After briefly moving offshore, it again made landfall near Mazatlán at 0800 UTC that day. Adolph soon dissipated over land, becoming the first of two storms to strike the Pacific coast of Mexico during the season. Because Hurricane Adolph weakened significantly prior to landfall, no deaths or major damage occurred. However, the remnants of the storm brought heavy showers and gusty winds to Florida. Although a modern Pacific hurricane season begins May 15, one newspaper considered Adolph a "pre-season" storm.

Hurricane Barbara

A tropical disturbance was first observed in early June about south of Guatemala, and headed westward. The tropical disturbance intensified, and became the second tropical depression of the season on June 9. After staying a tropical depression for 24 hours, the system was subsequently upgraded to Tropical Storm Barbara. Initially, Barbara was expected to come very close to the Mexican coast; however, this failed to happen. At first, Tropical Storm Barbara moved west-northwest, though on June 11, the cyclone turned west-northwest while gradually gaining intensity. At 1800 UTC on June 12, Barbara was estimated to have attained hurricane status while centered north of Clipperton Island. Shortly after becoming a hurricane, rapid deepening commenced, and by early the next morning, the hurricane was a high-end Category 1. Six hours later, Barbara skipped Category 2 status, and became a major hurricane. At 1800 UTC on June 13, Hurricane Barbara was upgraded into a category 4 hurricane on the SSHWS, with a peak strength of 130 mph (215 km/h).

Hurricane Barbara held on to peak intensity for a day. Thereafter, Barbara slowly weakened after peak intensity as it began to encounter cooler water temperatures, while moving slowly northward around the western edge of a high pressure area over central Mexico. By the early morning hours of June 16, the hurricane was positioned west-southwest of Socorro Island and about west of the coast of Mexico. Later that day, Barbara weakened into a tropical storm due to strong wind shear. Barbara was downgraded to a tropical depression early on June 17. Further weakening persisted, and Barbara dissipated on June 18. At the time of dissipation, the system was situated several hundred miles west-southwest of the Baja California peninsula.

Tropical Storm Cosme

A westward-moving low-latitude tropical disturbance was declared a tropical depression early on July 2. After making a turn northwest, the depression maintained its intensity for 42 hours. By 1200 UTC on July 4, the system was finally upgraded into a tropical storm after convection increased in coverage. However, Cosme failed to intensify further, and after encountering cooler waters, the storm rapidly dissipated. The EPHC declared Cosme dissipated at 1800 UTC on July 5.

Tropical Storm Dalilia

An intense area of thunderstorms developed south of the Gulf of Tehuantepec on July 4. The system was first classified as a tropical depression at 1800 UTC on July 5 roughly south-southeast of Acapulco. Turning west-northwest and then northwest while accelerating, the EPHC upgraded the depression into Tropical Storm Dalilia at 1800 UTC on July 6. Continuing to gain strength, Dalilia reached its peak intensity as a strong tropical storm early on July 8. After turning west the tropical storm started to lose strength while encountering colder water. At 0600 UTC on July 10, Tropical Storm Dalilia had been downgraded into a tropical depression. Two days later, the EPHC reported that the tropical cyclone had dissipated.

Tropical Storm Erick

Tropical Storm Erick originated from a tropical wave that crossed Central America on July 9 and July 10. At 0600 UTC on July 12, the EPHC reported that it had upgraded the disturbance into a tropical depression. The depression moved steadily west-northwest under the influence of an anticyclone over the Yucatán Peninsula. The system gradually intensified over waters as warm as and at 0000 UTC on July 13, the agency upgraded the low into a tropical storm. Tropical Storm Erick reached its peak intensity on July 14 as a high-end tropical storm. The storm maintained peak intensity for 24 hours, before encountering cooler water. Rapidly weakening, Erick dissipated on July 16 far from land.

Tropical Storm Flossie

A tropical disturbance developed southwest of Manzanillo late on July 16. Several hours later, the disturbance was classified as a tropical depression. Initially, the depression drifted southward, but at 1800 UTC on July 17, the system suddenly turned west-northwest and accelerated. The storm gradually intensified while passing northeast of Socorro Island. Midday on July 19, the tropical depression was upgraded into Tropical Storm Flossie. Six hours later, Tropical Storm Flossie reached its peak wind speed of . While the storm approached the Baja California peninsula, the storm ultimately turned west into an area of cool water and high amounts of wind shear. By 0000 UTC on July 21, Flossie weakened into a tropical storm. Twelve hours later, Flossie ceased to exist as a tropical cyclone.

Hurricane Gil