The 1999 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. The season officially began on May 15 in the Eastern Pacific proper (east of 140°W) and June 1 in the Central Pacific (140°W to the International Date Line), and ended on November 30 in both areas. This is historically the period during which most tropical cyclogenesis occurs in these respective areas. The first system, Hurricane Adrian, formed on June 18; the final system, Tropical Storm Irwin, dissipated on October 11.

Activity during the season was well below average. Nine named tropical storms developed, with six becoming hurricanes and two further strengthening into major hurricanes—Category 3 or higher on the five-level Saffir–Simpson scale. The season also produced five tropical depressions that did not attain tropical storm status. Only one tropical cyclone, Hurricane Greg, made landfall. It brushed central Mexico in its formative stages before striking the Baja California peninsula as a weakening tropical storm, killing ten people during its journey. Earlier in the season, flooding from peripheral rainfall produced by Hurricane Adrian caused several fatalities in Mexico. Also notable was Hurricane Dora, which was a rare tropical cyclone that existed in all three northern Pacific basins: Eastern, Central, and Western.

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 and the Central Pacific Hurricane Center 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.

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Timeline of events

May There were no tropical cyclones in May.

May 15 The 1999 Eastern Pacific hurricane season begins.

June June 1 The 1999 Central Pacific hurricane season begins.

June 18 06:00 UTC (11:00 p.m. PDT, June 17) at A tropical depression forms from a broad low-pressure area about southeast of Acapulco, Guerrero. 18:00 UTC (111:00 a.m. PDT) at The recently formed tropical depression strengthens into Tropical Storm Adrian about south of Acapulco.

June 20

00:00 UTC (5:00 p.m. PDT, June 19) at Tropical Storm Adrian strengthens into a Category 1 hurricane on the Saffir–Simpson scale about south-southeast of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Adrian strengthens to Category 2 intensity about south of the southern tip of the Baja California peninsula. It simultaneously attains its peak intensity, with maximum sustained winds of and a minimum central pressure of .

June 21 06:00 UTC (11:00 p.m. PDT, June 20) at Hurricane Adrian weakens to Category 1 intensity about south-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Adrian weakens into a tropical storm about south-southwest of the southern tip of the Baja California peninsula.

June 22 12:00 UTC (5:00 a.m. PDT) at Tropical Storm Adrian weakens into a tropical depression about southwest of the southern tip of the Baja California peninsula, and later dissipates.

July July 9 06:00 UTC (11:00 p.m. PDT, July 8) at A tropical depression forms from a low-pressure area about south of Lázaro Cárdenas, Michoacán. 12:00 UTC (5:00 a.m. PDT) at The recently formed tropical depression strengthens into Tropical Storm Beatriz about south-southwest of Lázaro Cárdenas.

July 11 12:00 UTC (5:00 a.m. PDT) at Tropical Storm Beatriz strengthens into a Category 1 hurricane about south-southwest of the southern tip of the Baja California peninsula.

July 12

00:00 UTC (5:00 p.m. PDT, July 11) at Hurricane Beatriz strengthens to Category 2 intensity about southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Beatriz strengthens to Category 3 intensity about southwest of the southern tip of the Baja California peninsula.

July 13 06:00 UTC (11:00 p.m. PDT, July 12) at Hurricane Beatriz attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , about southwest of the southern tip of Baja California.

July 14 06:00 UTC (11:00 p.m. PDT, July 13) at Hurricane Beatriz weakens to Category 2 intensity about west-southwest of the southern tip of the Baja California peninsula. 06:00 UTC (11:00 p.m. PDT, July 13) at Tropical Depression forms from a low-pressure area about southwest of Manzanillo, Colima. 12:00 UTC (5:00 a.m. PDT) at Tropical Depression attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , about west-southwest of Manzanillo.

July 15

06:00 UTC (11:00 p.m. PDT, July 14) at Hurricane Beatriz weakens to Category 1 intensity about west-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression is last noted as a tropical cyclone about southwest of the southern tip of the Baja California peninsula, dissipating shortly thereafter.

July 16 00:00 UTC (5:00 p.m. PDT, July 15) at Hurricane Beatriz weakens into a tropical storm about west of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Storm Beatriz weakens into a tropical depression about west of the southern tip of the Baja California peninsula.

July 17 00:00 UTC (5:00 p.m. PDT, July 16) at Tropical Depression Beatriz is last noted as a tropical cyclone about , dissipating shortly thereafter.

July 23

00:00 UTC (5:00 p.m. PDT, July 22) at Tropical Depression forms from a tropical wave about west-southwest of the southern tip of the Baja California peninsula. 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 , about west-southwest of the southern tip of the Baja California peninsula.

July 24 18:00 UTC (8:00 a.m. HST) at Tropical Depression crosses into the Central Pacfific basin about east-southeast of South Point, Hawaii.

July 25 00:00 UTC (2:00 p.m. HST, July 24) at Tropical Depression is last noted as a tropical cyclone about east-southeast of South Point, dissipating shortly thereafter. 06:00 UTC (11:00 p.m. PDT, July 24) at Another tropical depression forms from a tropical wave about south-southwest of the southern tip of the Baja California peninsula. 12:00 UTC (5:00 a.m. PDT) at The recently formed tropical depression strengthens into Tropical Storm Calvin about southwest of the southern tip of the Baja California peninsula. It simultaneously attains its peak intensity, with maximum sustained winds of and a minimum central pressure of .

July 26

12:00 UTC (5:00 a.m. PDT) at Tropical Storm Calvin weakens into a tropical depression about west-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression forms from a tropical wave about west-southwest of the southern tip of the Baja California peninsula.

July 27 06:00 UTC (11:00 p.m. PDT, July 26) at Tropical Depression Calvin is last noted as a tropical cyclone about west-southwest of the southern tip of the Baja California peninsula, dissipating shortly thereafter. 06:00 UTC (11:00 p.m. PDT, July 26) at Tropical Depression attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , about west-southwest of the southern tip of the Baja California peninsula.

July 28

00:00 UTC (5:00 p.m. PDT, July 27) at Tropical Depression is last noted as a tropical cyclone about west-southwest of the southern tip of the Baja California peninsula, dissipating shortly thereafter.

August August 6 00:00 UTC (5:00 p.m. PDT, August 5) at Tropical Depression forms from a tropical wave about south of Acapulco. 06:00 UTC (11:00 p.m. PDT, August 5) at Tropical Depression forms from a tropical wave about southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Dora about southwest of Acapulco. 18:00 UTC (11:00 a.m. PDT) at Tropical Depression strengthens into Tropical Storm Eugene about southwest of the southern tip of the Baja California peninsula.

August 8 12:00 UTC (5:00 a.m. PDT) at Tropical Storm Dora strengthens into a Category 1 hurricane about south-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Tropical Storm Eugene strengthens into a Category 1 hurricane about west-southwest of the southern tip of the Baja California peninsula.

August 9

00:00 UTC (5:00 p.m. PDT, August 8) at Hurricane Dora strengthens to Category 2 intensity about south-southwest of the southern tip of the Baja California peninsula. 06:00 UTC (11:00 p.m. PDT, August 8) at Hurricane Eugene strengthens to Category 2 intensity about west-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurrican Eugene attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , about west-southwest of the southern tip of the Baja California peninsula.

August 10 00:00 UTC (5:00 p.m. PDT, August 9) at Hurricane Dora strengthens to Category 3 intensity about southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Dora strengthens to Category 4 intensity about southwest of the southern tip of the Baja California peninsula.

August 11 00:00 UTC (5:00 p.m. PDT, August 10) at Hurricane Eugene weakens to Category 1 intensity about west-southwest of the southern tip of the Baja California peninsula. 12:00 UTC (2:00 a.m. HST) at Hurricane Eugene crosses into the Central Pacific basin about east-southeast of South Point.

August 12

00:00 UTC (5:00 p.m. PDT, August 11) at Hurricane Dora attains its peak intensity, with maximum sustained winds of and a minimum central pressure of , about west-southwest of the southern tip of the Baja California peninsula, making it the strongest storm of the season.

August 13 00:00 UTC (2:00 p.m. HST, August 12) at Hurricane Eugene weakens into a tropical storm about east-southeast of South Point. 12:00 UTC (5:00 a.m. PDT) at Tropical Depression forms from a tropical wave about south-southwest of the southern tip of the Baja California peninsula. 18:00 UTC (11:00 a.m. PDT) at Hurricane Dora weakens to Category 3 intensity about west of the southern tip of the Baja California peninsula. 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 , about southwest of the southern tip of the Baja California peninsula.

August 14 06:00 UTC (8:00 p.m. HST, August 13) at Hurricane Dora rapidly weakens to Category 1 intensity as it crosses into the Central Pacific basin about east of South Point. 18:00 UTC (8:00 a.m. HST) at Tropical Storm Eugene weakens into a tropical depression about south of South Point.

August 15

06:00 UTC (8:00 p.m. HST, August 14) at Hurricane Dora restrengthens to Category 2 intensity about east-southeast of South Point.