The 2020 Pacific hurricane season was a near average Pacific hurricane season in terms of named storms, featuring 17 (including one unnamed tropical storm which was operationally classified as a tropical depression), but well below average season for hurricanes and major hurricanes, with only 4 hurricanes and 3 major hurricanes forming. Additionally, no tropical cyclones formed in the Central Pacific basin for the first time since 2017. The season officially began on May 15 in the East Pacific Ocean (east of 140°W), and on June 1 in the Central Pacific (from 140°W to the International Date Line, north of the equator; they both ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the respective regions. However, the formation of tropical cyclones is possible at any time of the year, as illustrated in 2020 by the formation of the season's first system, Tropical Depression One-E, on April 25. This was the earliest formation of a tropical cyclone on record in the eastern Pacific basin proper. The final system of the season was Tropical Storm Polo, which dissipated on November 19.

The most significant storms of the season were Tropical Storm Amanda and Hurricane Genevieve. Amanda developed near Central America in late May and struck Guatemala, causing widespread damage in neighboring El Salvador and killing 40 people amid the COVID-19 pandemic in the latter country. Genevieve passed closely to the tip of the Baja California Peninsula in August, bringing hurricane-force winds and heavy rainfall, killing six and causing an estimated $50 million in damage. Otherwise, impact from other storms was minimal. In late July, Hurricane Douglas made an extremely close pass to Hawaii, with its weak southern eyewall crossing Oahu, causing minor effects. The remnant moisture of Tropical Storm Fausto contributed to the thunderstorms that brought about the August 2020 California lightning wildfires, and the remnants of Genevieve dropped heavy rainfall in Arizona and Southern California. Tropical Storm Hernan moved very near the coast of southwestern Mexico, causing an additional fatality and several millions of dollars' worth of damage. Collectively, the tropical cyclones of this season caused about US$301.4 million in damage and 47 deaths. __TOC__

Seasonal forecasts Record Namedstorms Hurricanes Majorhurricanes RefAverage (1981–2010): 15.4 7.6 3.2 Record high activity: 27 16† 11Record low activity: 8† 3 0† Date Source Namedstorms Hurricanes Majorhurricanes Ref May 20, 2020 SMN 15–18 8–10 4–5 May 21, 2020 NOAA 11–18 5–10 1–5 Area Namedstorms Hurricanes Majorhurricanes Ref Actual activity: EPAC 17 4 3 Actual activity: CPAC 0 0 0 Actual combined activity: 17 4 3 * May 15–November 30 only † Most recent of several such occurrences. (See all)

On May 20, 2020, the Servicio Meteorológico Nacional (SMN) issued its forecast for the season, predicting a total of 15–18 named storms, 8–10 hurricanes, and 4–5 major hurricanes to develop. The next day, the National Oceanic and Atmospheric Administration (NOAA) issued their outlook, calling for a below-normal to near-normal season with 11–18 named storms, 5–10 hurricanes, 1–5 major hurricanes, and an accumulated cyclone energy index of 60% to 135% of the median. Factors they expected to reduce activity were near- or below-average sea surface temperatures across the eastern Pacific and the El Niño–Southern Oscillation remaining in the neutral phase, with the possibility of a La Niña developing.

Seasonal summary

Although the hurricane season in the eastern Pacific did not officially begin until May 15, and on June 1 in the central Pacific, activity this year began several weeks prior with the formation of Tropical Depression One-E on April 25. This marked the earliest formation of a tropical cyclone on record in the eastern Pacific basin, surpassing 2017's Tropical Storm Adrian. Among relatively unfavorable conditions, the depression soon dissipated without developing further, and activity would not resume in the basin until nearly a month later with the formation of Tropical Depression Two-E near the coast of Guatemala on May 30. This system would later become Tropical Storm Amanda, the first named storm of the season and one of the worst natural disasters in El Salvador in around two decades. Not for nearly another month after Amanda, Tropical Depression Three-E would briefly become Tropical Storm Boris on June 25 well out to sea before weakening in the Central Pacific basin. A short-lived tropical depression would form near Baja California Sur just 2 days after Boris's dissipation and quickly weaken. Moving into July, Tropical Storm Cristina formed on July 6 and slowly intensified to a peak intensity of , barely missing hurricane status. Activity continued as yet another tropical depression, Six-E, formed on July 13 but quickly dissipated among the unfavorable conditions unfolding in the basin. Two more tropical systems formed in mid July, Tropical Depression Seven-E and Tropical Storm Douglas. Seven-E was short lived and although it did gain tropical storm intensity, it was operationally left unnamed. Douglas strengthened into the first hurricane of the season at 15:00 UTC on July 22, marking the fourth–latest date any season had gone without a hurricane. Douglas would later strengthen into a Category 4 hurricane and brush Hawaii with rain and gusty winds.

A burst of activity occurred in early August, with a tropical wave south of Mexico evolving into Tropical Storm Elida on August 9, later to become the second hurricane of the season. Elida was generally short lived, but with the formation of Tropical Depression Ten-E, Tropical Storm Fausto, and Hurricane Genevieve activity continued. Genevieve later became the second major hurricane of the season before briefly effecting Baja California Sur as a minimal hurricane. Two additional tropical cyclones, Tropical Storms Hernan and Iselle, formed in late August. Both were generally weak and did not make landfall, although the former brought heavy flooding and mudslides to western Mexico. Later, on September 5, the remnants of former Atlantic tropical cyclone Nana reformed into a new cyclone in the Pacific named Julio. After Julio, Karina and Lowell formed. Near the end of September, Hurricane Marie formed and rapidly intensified up to Category 4 strength before weakening out to sea, becoming the strongest storm of the season. The only October storm of the season, Norbert, lasted for 10 days. After almost a month of inactivity, Odalys formed on November 3, and dissipated three days later without affecting land. Tropical Storm Polo formed close to the end of the season, but it was also short-lived and weak.

The Accumulated Cyclone Energy (ACE) index for the 2020 Pacific hurricane season (Eastern Pacific and Central Pacific combined) as calculated by Colorado State University using data from the National Hurricane Center was 77.3 units. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of .

Systems Tropical Depression One-E

A disturbance developed within the Intertropical Convergence Zone (ITCZ) on April 17, aided by the passage of a convectively-coupled kelvin wave (CCKW) – an eastward-propagating area of enhanced thunderstorm activity near the equator. The disturbance moved westward within the ITCZ over the next several days, and after developing a well-defined center and organized convection, it was designated as Tropical Depression One-E at 06:00 UTC on April 25 about southwest of Baja California Sur. Moving northwestward, the depression retained organized deep convection until shortly after 00:00 UTC the next day. Dry air and westerly wind shear caused the depression to weaken and degenerate to a remnant low by 12:00 UTC. The remnant low turned west and opened up into a trough at 18:00 UTC on April 27.

Tropical Storm Amanda

The combination of an upper level low over northeastern Mexico and a passing CCKW over the East Pacific caused an area of low pressure to form south of Guatemala and El Salvador on May 27. Two days later, the system interacted with a tropical wave that first originated from Africa on May 18. The conglomeration of these features led to the formation of a tropical depression around 18:00 UTC on May 30; it was positioned about south of Puerto San José, Escuintla. Moving northeastward around the periphery of a large cyclonic gyre over northern Central America, the compact depression continued to organize, strengthening into Tropical Storm Amanda at 06:00 UTC the next day. About four hours later, Amanda made landfall at peak intensity near Las Lisas, Santa Rosa. Amanda rapidly degenerated as it moved inland, with its center dissipating around 18:00 UTC. The remnants of the system moved northward into the Bay of Campeche and redeveloped into the Atlantic's Tropical Storm Cristobal.

In El Salvador, torrential rainfall caused significant damage along coastal cities in the country as rivers overflowed and swept away buildings. Amanda killed 14 people in El Salvador, of which at least six died due to flash flooding, and one died from a collapsed home. More than 900 homes were damaged across the country and 1,200 families were evacuated to 51 shelters across La Libertad, San Salvador, Sonsonate, and San Vicente. In the capital, San Salvador, 50 houses were destroyed and 23 vehicles fell into a sinkhole. El Salvador President Nayib Bukele declared a 15-day national state of emergency due to the storm. Movement restrictions in place for the COVID-19 pandemic were temporarily lifted to allow people to purchase medicines, while hardware stores were allowed to open with limited capacity so people could purchase equipment for repairs.

Tropical Storm Boris

The interaction between a tropical wave, a preexisting area of disturbed weather, and the favorable phase of the Madden–Julian oscillation (MJO) led to the formation of a surface low late on June 23. Deep convection coalesced with this circulation over the ensuing hours, and a tropical depression developed around 06:00 UTC on June 24. The system struggled via the effects of nearby dry air and some wind shear as it moved west to west-northwest under the subtropical ridge. Nonetheless, it intensified into Tropical Storm Boris around 18:00 UTC on June 25 when deep convection was most prevalent. A further increase in upper-level winds prevented Boris from strengthening beyond minimal tropical storm intensity, and it instead weakened to a tropical depression again twelve hours later before crossing into the Central Pacific basin. All associated thunderstorm activity dissipated by June 28, and Boris degenerated to a remnant area of low pressure by 00:00 UTC that day. The post-tropical cyclone curved west-southwest and dissipated well south-southeast of the Hawaiian Islands on June 30.

Tropical Depression Four-E

A broad area of disturbed weather, at least partially enhanced by a tropical wave, formed near the Gulf of Tehuantepec on June 25. The system paralleled the Mexican coastline and only slowly organized over the coming days, eventually meeting the criteria to be designated a tropical depression around 18:00 UTC on June 29. Despite coalescing deeper convection near the center at the time of formation, Tropical Depression Four-E failed to attain winds greater than as it encountered hostile southwesterly wind shear and colder ocean waters. Instead, the system degenerated to a remnant area of low pressure by 18:00 UTC on June 30. The low turned north and dissipated well south of Baja California on July 1.

Tropical Storm Cristina