[8] PAGASA kept tracking the system until May 21,[3] when the remnants of Dom and a weakening Ellen began accelerating towards an extratropical cyclone south of Japan.

[7] As Ditang tracked towards the Philippines, PAGASA issued Public Storm Warning Signal (PSWS) #3 for Catanduanes, Camarines Norte and Sur, Aurora, Quirino, Cagayan, Mountain Province, Nueva Vizcaya, Ifugao, Batanes, and Abra.

Despite initially showing signs of weakening, the next day, it rapidly developed, becoming a tropical storm a few hours later, causing both the JTWC and JMA to issue their first advisories early on 13 May, with the former naming it Ellen.

[13] Shortly after, Ellen began recurving northwest towards Japan, weakening as it neared the extratropical cyclone which absorbed Dom.

[7][15] After making landfall in Shantou on 23 May with sustained winds of 55 kn (65 mph; 100 km/h), Georgia rapidly weakened, causing the JTWC to stop monitoring it the next day.

On 20 June, satellite imagery indicated increased convective activity around the eastern periphery of the trough as a result of convergent easterly flow.

[17][7] Slightly weakening, at 1800Z the next day, Herbert made its landfall in Hainan with maximum sustained winds of 45 kn (50 mph; 85 km/h).

[17] After tracking into the Gulf of Tonkin, on 28 June, Herbert made its second landfall south of Jinzhou, China with sustained winds of 45 kn (50 mph; 85 km/h).

[7] By 00:00 UTC on July 17, the surface center and the deep convection moved closer together, prompting the JTWC to classify the system as a tropical depression.

Despite maintaining its structure[22] as it tracked over the Leizhou Peninsula, the storm weakened as it entered the Gulf of Tonkin and approached the coast of Vietnam.

[22] Both the JTWC and JMA agree that Joe had winds of 130 km/h (80 mph) when it moved ashore near Haiphong in Vietnam later on July 22.

[7] Ten hours later, a Hurricane hunter aircraft measured a pressure of 908 mbar (26.81 inHg), causing the JTWC to declare Kim a super typhoon[25] and increasing the wind speed to 240 km/h (150 mph).

[7] Almost immediately thereafter, reports from the same Hurricane Hunter aircraft indicated that the pressure of the typhoon rose sharply, likely in response to decreased inflow caused by Kim's close proximity to land.

[7] On 6 August, due to atmospheric instability caused by a weakening Lex, an area of convection west of the Marshall Islands began developing.

[7][32] On 15 August, a weak area of convection associated with a TUTT located over the Marshall Islands began slowly coalescing.

[33][7] Steadily tracking west-northwestwards, the next day, the JTWC followed suit with upgrading it into a depression,[33] with PAGASA naming it Reming as it had crossed into the PAR.

[35] The ninth tropical cyclone to strike Japan during the season, Orchid killed six people in Kyushu and triggered devastating landslides on the country's main island of Honshu, causing crops to sustain heavy damage.

[37] The MV Derbyshire, a ship which was headed for Kawasaki with iron ore from Sept-Îles, Canada on July 11, was sunk by Orchid.

[7] Soon after, sypnotic data revealed that the system's circulation was developing, causing the JTWC to follow suit in upgrading it into a depression early the next day.

[7] Tracking northwestward, a few hours later, Ruth made landfall in Hainan Island with 1-minute sustained winds of 45 kn (50 mph; 85 km/h).

[40] As a result, according to the JTWC, Ruth underwent rapid intensification, peaking as a minimal typhoon with 1-minute sustained winds of 65 kn (75 mph; 120 km/h).

[40] The worst typhoon to strike Thanh Hoa province in 30 years,[41] a 2022 report from GeoHazards stated that from 1970 to 2018, Ruth was the tropical cyclone which caused the most crop damage in the area.

[43] On 13 September, a tropical disturbance located at the base of a mid-tropospheric trough extending south of Japan began developing.

[44] Rapidly weakening once inland, on 19 September, both the JTWC and JMA had ceased tracking it, with the former agency noting that Percy had dissipated at that time.

[44][3] As Percy scraped Taiwan, heavy rainfall damaged around 140 homes, destroyed crops, and flooded rice fields.

[7] Despite its eastward track preventing it from initially encountering colder waters and intense wind shear, Sperry began weakening around the time that it peaked.

[46] The JMA kept tracking Thelma, noting that it had deepened to attain a minimal central pressure of 960 mbar (28 inHg) on 2 October.

A Tropical Cyclone Formation Alert (TCFA) was issued when a reconnaissance aircraft observed a well-defined low-level circulation with a minimum sea-level pressure of 1004 mb.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration uses its own naming scheme for tropical cyclones in their area of responsibility.

This table will list all the storms that developed in the northwestern Pacific Ocean west of the International Date Line and north of the equator during 1980.