The 1984 Pacific hurricane season featured numerous tropical cyclones, several of which were impactful to land. It was a busy hurricane season with 21 named storms, 13 hurricanes, and 7 major hurricanes, the latter of which are Category 3 or stronger cyclones on the Saffir–Simpson scale. This activity was unusual given the presence of a La Niña, which typically suppresses Central and East Pacific tropical cyclone activity, and only average sea surface temperatures. Seasonal activity began on May 17 and ended on November 8. This lies within the confines of a traditional hurricane season which begins on May 15 in the East Pacific and June 1 in the Central Pacific, and ends on November 30 in both basins. These dates conventionally delimit the period during each year when most tropical cyclones form.
The drought-stricken Hawaiian Islands received beneficial rainfall from Hurricane Douglas in July and Tropical Storm Kenna in August. The remnants of hurricanes Iselle, Marie, Norbert, and Odile all contributed to enhanced precipitation across the Southwestern United States during the season, including snowfall in higher elevations; flash flooding killed one person in Texas. Hurricane Lowell attracted widespread coverage for damaging the Blue Falcon and forcing the rescue of its 23 crewmembers. In September, torrential rains from Hurricane Odile in Southern Mexico severely damaged crops, inflicted water damage to about 900 homes, and left thousands of residents displaced or without normal services. The storm killed at least 21 people. Multiple hurricanes contributed to rough surf along the California coastline, resulting in one death and hundreds of water rescues.
Systems
Tropical Storm Alma
On May 13, an area of disturbed weather within the Intertropical Convergence Zone (ITCZ) crossed Panama and Colombia into the East Pacific. Strong westerly wind shear inhibited this disturbance initially, but atmospheric conditions improved over subsequent days, allowing it to become the season's first tropical depression around 18:00 UTC on May 17. The system increased rapidly in size as developing high pressure to its north brought it over very warm ocean waters. The depression intensified into Tropical Storm Alma by 18:00 UTC on May 18, attaining peak winds of the next day. After fluctuating in intensity for a few days, Alma weakened to a tropical depression and dissipated after 18:00 UTC on May 21.
Hurricane Boris
A tropical depression developed south of the Gulf of Tehuantepec around 18:00 UTC on May 28. It intensified into Tropical Storm Boris over the next six hours, and further development allowed it to become the season's first hurricane by 12:00 UTC on May 30. After reaching peak winds of , Boris weakened and began to move erratically as upper-level troughing progressed over western Mexico. The storm conducted a counter-clockwise loop over numerous days, finally tracking west again as ridging redeveloped to its north. The system, which had persisted as a tropical depression during that time, regained tropical storm intensity on June 13 before crossing into cooler waters. Boris dissipated after 00:00 UTC on June 18 to the southwest of the Baja California Peninsula.
Hurricane Cristina
A weak cold-core low drifted westward across the southern Gulf of Mexico, acting as the impetus for a tropical depression that formed south of Mexico around 06:00 UTC on June 17. The depression intensified into Tropical Storm Cristina within six hours and further organized into a hurricane around 18:00 UTC on June7 19. The next day, it attained Category 2 strength with winds of . High pressure over Oklahoma, and upper-level troughing over southern California, both retrograded west as Cristina developed. This caused the storm to track in stair-step fashion throughout its duration. The cyclone weakened to a tropical storm on August 21, but it regained hurricane strength two days later before feeling the effects of an upper-level trough off Baja California. Cristina weakened rapidly, dissipating after 00:00 UTC on June 26.