Timeline of the 2018 Pacific hurricane season

The 2018 Pacific hurricane season was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the eastern Pacific Ocean. The season officially started on May 15 in the eastern Pacific—east of 140°W—and began on June 1 in the central Pacific—the region between the International Date Line and 140°W, and ended on November 30. These dates typically cover the period of each year when most tropical cyclones form in the eastern Pacific basin. The season began with the formation of Tropical Depression One-E, which developed on May 10, and ended with the dissipation of the season's final storm, Tropical Storm Xavier, which dissipated as a tropical cyclone on November 5.

The 2018 hurricane season was exceptionally active and featured the highest Accumulated Cyclone Energy since reliable records began in 1971. Throughout the season, 26 tropical depressions developed, 23 of which became tropical storms. A total of 13 tropical storms reached hurricane strength, and 10 hurricanes achieved major hurricane intensity. The basin saw above-average activity across all regions from the International Date Line to the west coast of Mexico and Central America. Activity peaked from early August to early October, with several long-lived and powerful hurricanes developing in that time period. Several storms severely affected land, such as Hurricane Lane in Hawaii and Hurricane Willa in Mexico. In contrast to the similarly active 2015 Pacific hurricane season, 2018 was not significantly influenced by the El Niño–Southern Oscillation. Instead, low pressures and increased sea surface temperatures associated with the Pacific Meridional Mode supported the development of these intense and long-lived storms.

This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season. It includes information that was not released throughout the season, meaning that data from post-storm reviews by the National Hurricane Center, such as a storm that was not initially warned upon, has been included.

The time stamp for each event is first stated using Coordinated Universal Time (UTC), the 24-hour clock where 00:00 = midnight UTC. The NHC uses both UTC and the time zone where the center of the tropical cyclone is currently located. The time zones utilized (east to west) are: Central, Mountain, Pacific and Hawaii. In this timeline, the respective area time is included in parentheses. Additionally, figures for maximum sustained winds and position estimates are rounded to the nearest 5 units (miles, or kilometers), following National Hurricane Center practice. Direct wind observations are rounded to the nearest whole number. Atmospheric pressures are listed to the nearest millibar and nearest hundredth of an inch of mercury.