The 1990 Pacific hurricane season was the annual cycle of tropical cyclone formation over the Pacific Ocean north of the equator and east of the International Date Line (IDL). The season officially began on May 15 in the Eastern Pacific basin proper (east of 140°W) and June 1 in the Central Pacific basin (140°W to the IDL), and ended on November 30 in both areas. This is historically the period during which most tropical cyclogenesis occurs in these respective areas. Activity during the season began three days early with the formation of Hurricane Alma on May 12. The final system to dissipate was Hurricane Trudy, which did so on November 1. Hurricane Vance formed a few days after Trudy, but dissipated roughly a day prior.

The 1990 season was extremely active, producing several long-lived and powerful hurricanes. A total of 21 named tropical storms developed, of which a record-breaking 16 strengthened into hurricanes. Six became major hurricanes by reaching Category 3 or higher on the five-level Saffir–Simpson scale, including hurricanes Hernan and Trudy, which were estimated by satellite to be amongst the strongest recorded Pacific hurricanes. Four tropical cyclones existed in the Central Pacific basin during the season, including two which formed there: a tropical storm, and a tropical depression which remained below tropical storm strength. Four other such tropical depressions formed in the Eastern Pacific basin proper; a fifth—Atlantic Hurricane Diana—crossed over Mexico and emerged offshore as a tropical depression shortly before dissipation.

Despite the activity, only one tropical cyclone made landfall during the 1990 season. Tropical Storm Rachel swept across the southern Baja California peninsula and into northwestern Mexico in early October. Heavy rainfall led to floods that killed 18 people. Earlier in the season, Tropical Storm Douglas narrowly skirted the coast of Mexico, while several tropical cyclones came within close proximity of Socorro Island.

This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, and dissipations during the season. It includes information that was not released during the season, meaning that data from post-storm reviews by the National Hurricane Center (NHC) and the Central Pacific Hurricane Center (CPHC) 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 was then located. Prior to 2015, two time zones were utilized in the Eastern Pacific basin: Pacific for the Eastern Pacific, and Hawaii−Aleutian for the Central Pacific. 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 NHC 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. __TOC__

Timeline of events

May May 12 18:00 UTC (11:00 a.m. PDT) at An off-season tropical cyclone, Tropical Depression , develops from a tropical wave while located about south of Zihuatanejo, Guerrero.

May 14 00:00 UTC (5:00 p.m. PDT, May 13) at Tropical Depression strengthens into Tropical Storm Alma while located about south of Manzanillo, Colima.

May 15

The 1990 Eastern Pacific hurricane season officially begins. 12:00 UTC (5:00 a.m. PDT) at Tropical Storm Alma strengthens into a Category 1 hurricane on the Saffir–Simpson scale while located about south-southwest of the southern tip of the Baja California peninsula, making it the earliest recorded hurricane in the Eastern Pacific basin proper.

May 16 06:00 UTC (11:00 p.m. PDT, May 15) at Hurricane Alma attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Alma weakens into a tropical storm while located about southwest of the southern tip of the Baja California peninsula.

May 17 18:00 UTC (11:00 a.m. PDT) at Tropical Storm Alma weakens into a tropical depression while located about southwest of the southern tip of the Baja California peninsula.

May 18 12:00 UTC (5:00 a.m. PDT) at Tropical Depression Alma is last noted as a tropical cyclone while located about west-southwest of the southern tip of the Baja California peninsula, dissipating shortly thereafter.

June June 1 The 1990 Central Pacific hurricane season officially begins.

June 2 18:00 UTC (11:00 a.m. PDT) at Tropical Depression develops from a tropical wave while located about south of Acapulco, Guerrero.

June 4 00:00 UTC (5:00 p.m. PDT, June 3) at Tropical Depression strengthens into Tropical Storm Boris while located about southwest of Manzanillo.

June 5 00:00 UTC (5:00 p.m. PDT, June 4) at Tropical Storm Boris strengthens into a Category 1 hurricane while located about south-southwest of the southern tip of the Baja California peninsula. 12:00 UTC (5:00 a.m. PDT) at Hurricane Boris attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about south-southwest of the southern tip of the Baja California peninsula.

June 6

12:00 UTC (5:00 a.m. PDT) at Hurricane Boris weakens into a tropical storm while located about west-southwest of the southern tip of the Baja California peninsula.

June 7 06:00 UTC (11:00 p.m. PDT, June 6) at Tropical Storm Boris weakens into a tropical depression while located about west of the southern tip of the Baja California peninsula.

June 8 12:00 UTC (5:00 a.m. PDT) at Tropical Depression Boris is last noted as a tropical cyclone while located about south-southwest of Punta Eugenia, Baja California Sur, dissipating shortly thereafter. 12:00 UTC (5:00 a.m. PDT) at Tropical Depression develops from a tropical wave while located about south of the southern tip of the Baja California peninsula.

June 9 12:00 UTC (5:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Cristina while located about south of the southern tip of the Baja California peninsula.

June 12

12:00 UTC (5:00 a.m. PDT) at Tropical Storm Cristina attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about south-southwest of the southern tip of the Baja California peninsula.

June 14 00:00 UTC (5:00 p.m. PDT, June 13) at Tropical Storm Cristina weakens into a tropical depression while located about west-southwest of the southern tip of the Baja California peninsula.

June 16 12:00 UTC (5:00 a.m. PDT) at Tropical Depression Cristina dissipates while located about west-southwest of the southern tip of the Baja California peninsula.

June 19 00:00 UTC (5:00 p.m. PDT, June 18) at Tropical Depression develops from a tropical wave while located about south of Acapulco. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Douglas while located about southwest of Acapulco.

June 21 12:00 UTC (5:00 a.m. PDT) at Tropical Storm Douglas attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about south of Manzanillo.

June 23

12:00 UTC (5:00 a.m. PDT) at Tropical Storm Douglas weakens into a tropical depression while located about southeast of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression Douglas is last noted as a tropical cyclone while located about south-southeast of the southern tip of the Baja California peninsula, dissipating shortly thereafter.

June 26 06:00 UTC (11:00 p.m. PDT, June 25) at Tropical Depression develops from a tropical wave while located about southwest of Acapulco. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Elida while located about west-southwest of Acapulco.

June 28 00:00 UTC (5:00 p.m. PDT, June 27) at Tropical Storm Elida strengthens into a Category 1 hurricane while located about southeast of Socorro Island. 06:00 UTC (11:00 p.m. PDT, June 27) at Hurricane Elida attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about southeast of Socorro Island.

June 29

12:00 UTC (5:00 a.m. PDT) at Hurricane Elida weakens into a tropical storm while located about west-northwest of Socorro Island. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression develops from an area of unsettled weather while located about south of Acapulco.

July July 1 00:00 UTC (5:00 p.m. PDT, June 30) at Tropical Storm Elida weakens into a tropical depression about west of Socorro Island.

July 2 12:00 UTC (5:00 a.m. PDT) at Tropical Depression Elida is last noted as a tropical cyclone about west of Socorro Island, dissipating shortly thereafter.

July 3 18:00 UTC (11:00 a.m. PDT) at Tropical Depression attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about west of Manzanillo, dissipating shortly thereafter.

July 6 00:00 UTC (5:00 p.m. PDT, July 5) at Tropical Depression develops from a tropical wave while located about south-southwest of Acapulco.

July 7 00:00 UTC (5:00 p.m. PDT, July 6) at Tropical Depression strengthens into Tropical Storm Fausto while located about south of Manzanillo.

July 8

12:00 UTC (5:00 a.m. PDT) at Tropical Storm Fausto strengthens into a Category 1 hurricane while located about south of the southern tip of the Baja California peninsula.

July 9 00:00 UTC (5:00 p.m. PDT, July 8) at Hurricane Fausto attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about south-southwest of the southern tip of the Baja California peninsula.

July 10 00:00 UTC (5:00 p.m. PDT, July 9) at Tropical Depression develops from a tropical wave while located about south-southeast of Puerto Ángel, Oaxaca. 06:00 UTC (11:00 p.m. PDT, July 9) at After weakening slightly, Hurricane Fausto reattains its peak intensity while located about west of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Fausto weakens into a tropical storm while located about west of the southern tip of the Baja California peninsula.

July 11 18:00 UTC (11:00 a.m. PDT) at Tropical Storm Fausto weakens into a tropical depression while located about southwest of Punta Eugenia. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Genevieve while located about west-southwest of Puerto Ángel.

July 12 18:00 UTC (11:00 a.m. PDT) at Tropical Depression Fausto is last noted as a tropical cyclone while located about west-southwest of Punta Eugenia, dissipating shortly thereafter.

July 13 00:00 UTC (5:00 p.m. PDT, July 12) at Tropical Storm Genevieve strengthens into a Category 1 hurricane while located about southeast of Socorro Island.

July 15

00:00 UTC (5:00 p.m. PDT, July 14) at Hurricane Genevieve strengthens to Category 2 intensity while located about west of Socorro Island. 12:00 UTC (5:00 a.m. PDT) at Hurricane Genevieve attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , while located about west-northwest of Socorro Island.

July 16 06:00 UTC (11:00 p.m. PDT, July 15) at Hurricane Genevieve weakens to Category 1 intensity while located about west-northwest of Socorro Island.

July 17 00:00 UTC (5:00 p.m. PDT, July 16) at Hurricane Genevieve weakens into a tropical storm while located about southwest of Punta Eugenia.

July 18 00:00 UTC (5:00 p.m. PDT, July 17) at Tropical Storm Genevieve weakens into a tropical depression while located about west-southwest of Punta Eugenia.