The 2017 Pacific hurricane season was a near average season, featuring eighteen named storms, nine hurricanes, and four major hurricanes, although, the season was significantly less active than the previous three seasons, and most of these storms were weak and short-lived. The season officially started on May 15 in the eastern Pacific, and on June 1 in the central Pacific; they both ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the two basins. However, the formation of tropical cyclones is possible at any time of the year. This was demonstrated when the first storm, Tropical Storm Adrian, was named on May 10, and became the earliest-known tropical storm in the Eastern Pacific. The season saw near-average activity in terms of ACE, in stark contrast to the extremely active seasons in 2014, 2015, and 2016; for the first time since 2012, no tropical cyclones formed in the Central Pacific basin. However, for the third year in a row, the season featured above-average activity in July, with the ACE value being the fifth highest for the month.
On May 5, the National Hurricane Center forecasted an area of low pressure to form south of Mexico over a few days, with tropical cyclone development possible thereafter. A broad circulation developed late on May 7, eventually forming into Tropical Depression One-E at 21:00 UTC on May 9. As it formed, it became the earliest-forming Eastern Pacific tropical cyclone on record, beating Hurricane Alma of 1990 which formed on May 12. It later intensified into Tropical Storm Adrian at 03:00 UTC on May 10, the earliest-known formation of a named storm in the Eastern Pacific since the start of the satellite era. It was originally forecast to become a strong hurricane, but after peaking at 45 mph on early May 10, an increase in wind shear quickly stripped and degenerated Adrian and became a remnant low at 00:00 UTC on May 11. The remnant low survived for another day before dissipating completely on May 12.
Beatriz's origins can be traced back to a tropical wave that left the coast of west Africa on May 18, that uneventfully crossed the Atlantic; entering the East Pacific around a week later. It started to steadily organize and was dubbed, Tropical Depression Two-E at 12:00 UTC on May 31. It started to move northeast and intensified to Tropical Storm Beatriz at 06:00 UTC on June 1. It attained a peak of 45 mph (75 km/h), and then made landfall around 00:00 UTC on June 2 about 25 miles west of Puerto Angel, Mexico. After landfall, the mountains in Mexico quickly shredded Beatriz and dissipated twelve hours later.
In the end, 7 deaths occurred between the states of Oaxaca and Tehuantepec and a total of 70 million pesos ($3.7 Million USD) in damages occurred between Beatriz and Tropical Storm Calvin.
As June progressed, the NHC forecast another broad low pressure system to develop south of Mexico over several days, and on June 9 and a tropical disturbance formed, where it continued to develop into Tropical Depression Three-E at 12:00 UTC on June 11, it organized slowly because of moderate easterly wind shear as it slowly moved northwestward. At 18:00 UTC on June 12, Three-E intensified into Tropical Storm Calvin. It continued to intensify briefly to peak at 45 mph (75 km/h), and then made landfall between Salina Cruz and Puerto Angel, Mexico at 00:00 UTC on June 13. 12 hours later, Calvin dissipated and the remnants caused some minor flooding and heavy rainfall, however no fatalities occurred.
Around June 21, a trough developed and started to drift around south of the Gulf of Tehuantepec for a couple days. On June 23, the remnants of Bret from the Atlantic merged with the trough, and a surface low formed early on June 24. It started getting organized and developed into Tropical Depression Four-E at 18:00 UTC. It drifted west-northwestward and at 06:00 UTC on June 25, Four-E intensified into Tropical Storm Dora. Dora then entered an area of favorable conditions, and started to undergo rapid intensification as a result, becoming a Category 1 hurricane at 06:00 UTC on June 26 and a Category 2 hurricane at 12:00 UTC. Dora later peaked with winds of 105 mph (165 km/h) and a minimum pressure of 974 mbar (28.8 inHg) at 18:00 UTC on June 26.
Dora maintained Category 2 strength for 12 more hours before entering a more hostile environment of cool sea temperatures and dry air. It slowly deteriorated and degenerated into a remnant low near Socorro Island on June 28. It continued to meander around the eastern Pacific until it completely dissipated on July 1. Damages were minor, but the outer bands brought heavy rains to Guerrero, Mexico which caused flooding problems.
On July 7, a disturbance south of the tip of the Baja California Peninsula developed into Tropical Depression Five-E, and six hours later intensified into Tropical Storm Eugene. On July 8, the new tropical storm began to undergo rapid intensification and from 21:00 UTC on July 8 to 15:00 UTC on July 9, Eugene went from winds of 70 mph to 115 mph; which made it the first major hurricane of the season. Then, at 03:00 UTC the next day, dry air started to impact Eugene, and weakened to a Category 2 hurricane as a result. The next day, Eugene started experiencing cooler waters and weakened to a tropical storm the next day. Convection continued to die off, and Eugene weakened to a tropical depression at 15:00 UTC on July 12, and six hours later, degenerated to a remnant low.
The following names were used for named storms that formed in the northeastern Pacific Ocean during 2017. No names were retired after this season, so this list will be used again in the 2023 season. This same list was used in the 2011 season.
For storms that form in the Central Pacific Hurricane Center's area of responsibility, encompassing the area between 140 degrees west and the International Date Line, all names are used in a series of four rotating lists. The next four names that were slated for use in 2017 are shown below, however none of them were used.
This is a table of all the storms that formed in the 2017 Pacific hurricane season. It includes their duration, names, landfall(s), denoted in parentheses, damages, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all the damage figures are in 2017 USD.