The 2010 Pacific hurricane season was one of the least active seasons on record, featuring the fewest named storms since 1977. The season officially started on May 15 in the eastern Pacific—east of 140°W—and on June 1 in the central Pacific—between the International Date Line and 140°W—and lasted until November 30. These dates typically cover the period of each year when most tropical cyclones form in the eastern Pacific basin. The season's first storm, Tropical Storm Agatha, developed on May 29; the season's final storm, Tropical Storm Omeka, degenerated on December 21.

The season began with record-breaking activity with four named storms, including two major hurricanes, developing by the end of June. Accumulated cyclone energy (ACE)Accumulated Cyclone Energy, broadly speaking, is a measure of the power of a hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. values exceeded 300 percent of the average for the month of June. Activity abruptly diminished thereafter, with July, August, and September seeing record low storm development. The Eastern Pacific season proper ended with Tropical Storm Georgette's dissipation on September 23, a month before the climatological mean. The year's final cyclone, Omeka, developed in the off-season on December 18, marking a record-late formation date in the satellite-era.

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 and the Central Pacific 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. Four time zones are utilized in the basin: Central for storms east of 106°W, Mountain between 114.9°W and 106°W, Pacific between 140°W and 115°W, and Hawaii–Aleutian for storms between the International Date Line and 140°W. 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. __TOC__

Timeline of events

May

May 15 The 2010 Pacific hurricane season officially begins.

May 29

00:00 UTC (7:00 p.m. CDT, May 28) – Tropical Depression One-E develops out of a broad area of low pressure roughly southwest of Tapachula, Mexico. 06:00 UTC (1:00 a.m. CDT) – Tropical Depression One-E intensifies into a tropical storm and is named Agatha while located about southwest of Guatemala City, Guatemala. 18:00 UTC (1:00 p.m. CDT) – Tropical Storm Agatha reaches its peak intensity with winds of and a barometric pressure of 1001 mbar (hPa; ). 22:30 UTC (5:30 p.m. CDT) – Tropical Storm Agatha makes landfall near Champerico, Guatemala, just south of the Mexico–Guatemala border, while at peak strength.

May 30 06:00 UTC (1:00 a.m. CDT) – Agatha weakens to a tropical depression. 12:00 UTC (7:00 a.m. CDT) – Tropical Depression Agatha degenerates into a remnant low before subsequently dissipating six hours later over the high terrain of Guatemala.

June

June 1 The 2010 Central Pacific hurricane season officially begins.

June 16 06:00 UTC (1:00 a.m. CDT) – Tropical Depression Two-E develops out of a tropical wave roughly south of Salina Cruz, Mexico. 18:00 UTC (1:00 p.m. CDT) – Tropical Depression Two-E attains its peak intensity with winds of and a pressure of 1007 mbar (hPa; ).

June 17 06:00 UTC (1:00 a.m. CDT) – Tropical Depression Two-E rapidly dissipates off the coast of Mexico. 06:00 UTC (1:00 a.m. CDT) – Tropical Depression Three-E develops out of an area of low pressure roughly south-southwest of Manzanillo, Mexico. 12:00 UTC (7:00 a.m. CDT) – Observations from the ship Maersk Dhahran indicate that Three-E intensified into a tropical storm; the system was accordingly assigned the name Blas.

June 18 18:00 UTC (1:00 p.m. CDT) – Tropical Depression Four-E develops out of large, well-defined low-pressure area located about southeast of Acapulco, Mexico.

June 19

12:00 UTC (6:00 a.m. MDT) – Tropical Storm Blas reaches its peak intensity with winds of and a pressure of 994 mbar (hPa; ) while located about south of the southern tip of Baja California Sur. 12:00 UTC (7:00 a.m. CDT) – Tropical Depression Four-E intensifies into Tropical Storm Celia while situated roughly south-southeast of Acapulco, Mexico.

June 20 18:00 UTC (1:00 p.m. CDT) – Tropical Storm Celia intensifies into a Category 1 hurricane on the Saffir–Simpson hurricane wind scale while located south of Acapulco, Mexico.

June 21 00:00 UTC (5:00 p.m. PDT, June 20) – Tropical Storm Blas weakens to a tropical depression about southwest of the southern tip of Baja California Sur. 18:00 UTC (11:00 a.m. PDT) – Tropical Depression Blas degenerates into a non-convective remnant low roughly 710 mi (1,145 km) southwest of the southern tip of Baja California Sur.

June 22 06:00 UTC (1:00 a.m. CDT) – Hurricane Celia reaches Category 2 status and its initial peak intensity with winds of and a pressure of 973 mbar (hPa; ).

June 23 00:00 UTC (6:00 p.m. MDT, June 22) – Hurricane Celia weakens to Category 1 strength approximately south-southwest of Manzanillo, Mexico. 00:00 UTC (7:00 p.m. CDT, June 22) – Tropical Depression Five-E develops from an area of showers and thunderstorms about south-southeast of Salina Cruz, Mexico. 06:00 UTC (1:00 a.m. CDT) – Tropical Depression Five-E strengthens into Tropical Storm Darby about south-southeast of Salina Cruz, Mexico. 12:00 UTC (6:00 a.m. MDT) – Hurricane Celia regains Category 2 intensity while located southwest of Manzanillo, Mexico.

June 24 06:00 UTC (1:00 a.m. CDT) – Tropical Storm Darby rapidly strengthens into a Category 1 hurricane approximately south-southwest of Salina Cruz, Mexico. 12:00 UTC (6:00 a.m. MDT) – Hurricane Celia intensifies into Category 3 hurricane about south-southwest of Socorro Island. 18:00 UTC (12:00 p.m. MDT) – Hurricane Celia rapid intensifies into a Category 4 hurricane about south-southwest of Socorro Island.

June 25 00:00 UTC (5:00 p.m. PDT, June 24) – Hurricane Celia reaches its peak intensity as a Category 5 hurricane with winds of and a pressure of 921 mbar (hPa; ), about southwest of Socorro Island. 06:00 UTC (1:00 a.m. CDT) – Hurricane Darby intensifies into a Category 2 hurricane about south of Acapulco, Mexico. 12:00 UTC (5:00 a.m. PDT) – Stable environmental conditions and cooler waters result in Hurricane Celia weakening to a Category 4 system approximately southwest of Socorro Island. 12:00 UTC (7:00 a.m. CDT) – Hurricane Darby undergoes a second phase of rapid deepening and reaches Category 3 intensity about south-southwest of Acapulco, Mexico. 18:00 UTC (11:00 a.m. PDT) – Hurricane Celia weakens to Category 3 strength about southwest of Socorro Island. 21:00 UTC (4:00 p.m. CDT) – Hurricane Darby attains its peak intensity with winds of and a pressure of 959 mbar (hPa; ) approximately southwest of Acapulco, Mexico.

June 26 06:00 UTC (11:00 p.m. PDT, June 25) – Hurricane Celia weakens to Category 2 strength about 665 mi (1,070 km) west-southwest of Socorro Island. 12:00 UTC (7:00 a.m. CDT) – Increasing wind shear stemming from the large circulation of Hurricane Alex over the Gulf of Mexico causes Darby to weaken to a Category 2 hurricane about southwest of Acapulco, Mexico. 18:00 UTC (11:00 a.m. PDT) – Hurricane Celia weakens to Category 1 strength about 745 mi (1,200 km) west-southwest of Socorro Island.

June 27

00:00 UTC (5:00 p.m. PDT, June 26) – Hurricane Celia weakens to a tropical storm roughly 790 mi (1,270 km) west-southwest of Socorro Island. 00:00 UTC (7:00 p.m. CDT, June 26) – Hurricane Darby weakens to a Category 1 hurricane approximately southwest of Acapulco, Mexico. 06:00 UTC (1:00 a.m. CDT) – Hurricane Darby weakens to a tropical storm roughly southwest of Acapulco, Mexico.

June 28 12:00 UTC (7:00 a.m. CDT) – After doubling back to the east, Tropical Storm Darby weakens to a tropical depression about south of Acapulco, Mexico. 18:00 UTC (11:00 a.m. PDT) – Tropical Storm Celia degenerates into a non-convective remnant low approximately 1,035 mi (1,665 km) west-southwest of the southern tip of Baja California Sur. 18:00 UTC (1:00 p.m. CDT) – Tropical Depression Darby degrades into a remnant low about south-southeast of Acapulco, Mexico.

July

July 14 12:00 UTC (7:00 a.m. CDT) – Tropical Depression Six-E develops from a well-defined low about south-southwest of Manzanillo, Mexico. It simultaneously reaches its peak intensity with winds of and a pressure of 1006 mbar (hPa; ).

July 16 18:00 UTC (12:00 a.m. MDT) – Tropical Depression Six-E degenerates into a remnant low about west-southwest of Socorro Island.

August

August 6

00:00 UTC (7:00 p.m. PDT, August 5) – Tropical Depression Seven-E develops from a weak low roughly southwest of Acapulco, Mexico. 12:00 UTC (7:00 a.m. PDT) – Tropical Depression Seven-E intensifies into Tropical Storm Estelle approximately west of Acapulco, Mexico.

August 8 00:00 UTC (6:00 p.m. MDT, August 7) – Tropical Storm Estelle reaches its peak intensity with winds of and a pressure of 994 mbar (hPa; ) while situated southeast of Socorro Island.

August 9 18:00 UTC (12:00 p.m. MDT) – Tropical Storm Estelle weakens to a tropical depression roughly southwest of Socorro Island.

August 10 06:00 UTC (12:00 a.m. MDT) – Tropical Depression Estelle degenerates into a remnant low about southwest of Socorro Island.

August 20 06:00 UTC (12:00 a.m. MDT) – Tropical Depression Eight-E develops west-southwest of Manzanillo, Mexico. 18:00 UTC (12:00 p.m. MDT) – Tropical Depression Eight-E reaches its peak intensity with winds of and a pressure of 1003 mbar (hPa; ) while located about west of Manzanillo, Mexico.

August 21 18:00 UTC (12:00 p.m. MDT) – Tropical Depression Eight-E degenerates into a non-convective remnant low approximately southwest of the southern tip of Baja California Sur. 1800 UTC (1:00 p.m. CDT) – Tropical Depression Nine-E forms from an area of disturbed weather roughly southeast of Salina Cruz, Mexico.

August 22

12:00 UTC (7:00 a.m. CDT) – Tropical Depression Nine-E strengthens into a tropical storm and receives the name Frank while situated about south of Salina Cruz, Mexico.

August 25 12:00 UTC (7:00 a.m. CDT) – Tropical Storm Frank intensifies into a Category 1 hurricane about south of Manzanillo, Mexico.

August 26 18:00 UTC (12:00 p.m. MDT) – Hurricane Frank reaches its peak intensity with winds of and a pressure of 978 mbar (hPa; ) approximately southeast of Socorro Island.

August 27 06:00 UTC (12:00 a.m. MDT) – Hurricane Frank makes its closest approach to Socorro Island, passing within to the southwest. 18:00 UTC (12:00 p.m. MDT) – Hurricane Frank weakens to a tropical storm roughly west-northwest of Socorro Island.

August 28 12:00 UTC (6:00 a.m. MDT) – Tropical Storm Frank weakens to a tropical depression about north-northwest of Socorro Island. 18:00 UTC (12:00 p.m. MDT) – Tropical Depression Frank degenerates into a remnant low approximately north-northwest of Socorro Island.

September

September 3

00:00 UTC (6:00 p.m. MDT, September 2) – Tropical Depression Ten-E develops from a tropical wave about south-southeast of the southern tip of Baja California Sur. It simultaneously reaches its peak intensity with winds of and a pressure of 1003 mbar (hPa; ).