The 1990 Pacific typhoon season was another active season, with 31 storms being named during the year. It had no official bounds; it ran year-round in 1990, but most tropical cyclones formed in the northwestern Pacific Ocean between May and November.Gary Padgett. May 2003 Tropical Cyclone Summary. Retrieved 2006-08-26. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.

The scope of this article is limited to the Pacific Ocean, north of the equator and west of the International Date Line. Storms that form east of the date line and north of the equator are called hurricanes; see 1990 Pacific hurricane season. Tropical Storms formed in the entire west Pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions in this basin have the "W" suffix added to their number. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names.

Season summary

Systems 41 tropical cyclones formed this year in the Western Pacific, of which 31 became tropical storms. 19 storms reached typhoon intensity, of which 4 reached super typhoon strength.

Severe Tropical Storm Koryn

On January 12, both the JMA and the JTWC identified a tropical depression in the northwest Pacific Ocean.Joint Typhoon Warning Center. Retrieved on 2007-12-26. The depression intensified over the period of a day to become a tropical storm on January 13, when it received the name Koryn from the JTWC. According to them, but not the JMA, Koryn reached typhoon strength on January 15, when it peaked in intensity. The storm then weakened quite rapidly until it became extratropical on January 17, at 0000 UTC.

Tropical Storm Lewis

A tropical disturbance formed 200 miles south of Chuuk on April 26. The system tracked northward and the JTWC named it Lewis a few days later on the 29th. Lewis struggled to maintain tropical storm strength as the top of the storm was sheared off by strong westerlies. The storm slowly dissipated over water on May 3.

Typhoon Marian

An area of persistent convection formed in low latitudes south of Yap on May 9. The unorganized disturbance passed over the southern islands of the Philippines and was upgraded to a tropical storm, being named Marian on the 15th. The storm steadily intensified and reached peak intensity on the 17th. Marian began to recurve as it got caught up in an approaching cold front. Marian brushed Hong Kong and southern China, causing light rains and windy conditions. Marian made landfall on Taiwan on the 19th as a tropical storm. Despite being weak at landfall, Marian had a significant impact on Taiwan's agricultural industry, with losses at NT$270 million (US$10 million). Two fishermen were also swept away. Marian rapidly weakened from the mountainous terrain and transitioned to extratropical later that day.

Tropical Depression 04W

A weak low-level circulation formed in the South China Sea on June 14. Strong vertical shear prevented further development. The system was absorbed by Nathan when it entered the South China Sea.

Severe Tropical Storm Nathan (Akang)

A tropical disturbance formed on June 14 and trekked across the Philippines. The system created flooding across the entire archipelago, causing damages of ₱200 million (US$8.4 million), 64 deaths, and 8 missing. The depression was upgraded to Tropical Storm Nathan on the 16th. Nathan curved to the southwest as it interacted with Tropical Depression 04W. Nathan reached peak intensity of 65 mph (100 km/h) shortly before striking Hainan on the 18th. In the South China Sea, the cargo ship Tien Fu sank, killing 3 crewmen and leaving the captain missing. Two people drowned in Hong Kong. Similarly, two people were swept overboard and drowned in Macau. Torrential rains caused flooding in Guangdong, killing 10. Nathan caused about CN¥1.9 million (US$400,000) in Shantou. Nathan continued northwestwards, making its final landfall over the Vietnam/China border and dissipating over the mountains of northern Vietnam on the 19th.

Typhoon Ofelia (Bising)

An area of convection formed within the monsoon trough and became a tropical depression east of the Philippines on June 17. It tracked to northwestward, slowly organizing into a tropical storm the following day. The storm was named Ofelia. Initial vertical wind shear decreased and Ofelia intensified to a typhoon, peaking at 100 mph (155 km/h) as it approached Taiwan. Ofelia paralleled the Philippines, causing ₱60 million (US$2.5 million) in damages and 8 deaths. Ofelia made landfall over Taiwan on June 23, rapidly weakening before striking Zhejiang later that day. Torrental flooding in Taiwan caused devastating agricultural damage, with losses exceeding NT$2.55 billion (US$93 million), as well as 12 deaths and 25 missing. In China, CN¥338 million (US$114.7 million) in damages occurred in Fujian and Zhejiang. Over 30 deaths were reported as well. The storm merged with a frontal boundary while approaching the Korean Peninsula.

Typhoon Percy (Klaring)

An area of convection formed within the Caroline Islands at the eastern end of the monsoon trough. The disturbance rapidly intensified to a tropical storm, being named Percy on the 21st. Percy moved southwestward then curved northwestward towards the Philippines. Several islands of the western Caroline Islands, including Yap and Palau experienced devastating damage with one death reported on Palau. Percy developed an additional outflow channel and reached peak intensity of 130 mph (215 km/h) before slightly weakening and striking northern Luzon on the 27th. Eight deaths and two missing were reported but damage was minimal. Percy remained a weak typhoon until making landfall over southeastern China on the 29th. In Hong Kong, heavy rain caused flooding and one death. Over CN¥76 million (US$16 million) in damages, six killed, and 2 missing were reported in Guangdong and Fujian. Percy dissipated over land on the 30th, with its remnants causing further flooding in the Korean Peninsula and Japan.

Tropical Storm Robyn (Deling)

The outskirts of the storm brought of rainfall to Vladivostok in the Russian Far East.

Severe Tropical Storm Tasha (Emang)

65 mph Tropical Storm Tasha, which developed on July 21 and meandered through the South China Sea, hit southern China on the 30th, 75 miles east of Hong Kong. The storm caused torrential flooding in southern China, causing widespread damage and 108 fatalities. Tasha caused approximately 391 million RMB (US$71.2 million) in damage.

Typhoon Steve

Steve recurved out at sea.

Typhoon Vernon

Vernon followed Typhoon Steve's track.

Severe Tropical Storm Winona

The origins of Winona can be traced back to Severe Tropical Storm Tasha. On August 2, the remnant low of Tasha, as a patch of thunderstorms over northeastern China, was pushed to the east by a weather front from the west. By August 4, Tasha entered the Yellow Sea, before being pushed south by an anticyclone off northeastern Korea, into the East China Sea. Although the same system, Tasha was named Winona, as it started to strengthen into a tropical storm by August 7. It reached peak intensity with an eye-like feature on August 8, before landfalling over Japan the next day. Later, the remnants became extratropical.

Typhoon Yancy (Gading)

Typhoon Yancy killed 12 people in the Philippines after a landslide destroyed a dormitory. In China, severe damage occurred and at least 216 people were killed. 20 people were killed in Taiwan.

Tropical Storm Aka On 15:00 UTC on August 13, a weakening Tropical Storm Aka crossed into the basin from the Central Pacific, resulting in the Central Pacific Hurricane Center (CPHC) passing its responsibility to the Joint Typhoon Warning Center (JTWC). The next day, the JTWC downgraded Aka into a tropical depression since it had lost convection due to persistent wind shear caused by a nearby TUTT. On 12:00 UTC on August 15, the JTWC issued the last warning on the system, as it passed south of Wake Island.

Typhoon Zola

On August 15, a large area of convection associated with the inflow of developing Typhoon Yancy was cut off, as Yancy was moving too fast to the west for the convection in the east to be absorbed into Yancy. By August 16, the convection developed a mid to low level circulation, and developed into tropical storm by August 18. Zola intensified into a typhoon by the next day, before reaching peak intensity on August 21. By the next day, Zola made landfall over Japan, before dissipating north of Japan. High winds and heavy rains produced by the storm killed six people and injured 22 others in Japan.

Typhoon Abe (Iliang)

Forming on August 23 from a tropical disturbance, the depression which would eventually develop into Typhoon Abe initially tracked in a steady west-northwestward direction. As a result of an intense monsoon surge, the system's trajectory briefly changed to an eastward then northward path before returning to its original track. Abe only intensified by a small amount between 0000 UTC August 24 and 0600 UTC August 27 due to the disruptive effects of the surge, and on August 30, Abe peaked in intensity as a Category 2-equivalent typhoon on the Saffir–Simpson hurricane wind scale. After peaking in intensity, Abe crossed the Ryukyu Islands and the East China Sea, making landfall in China where it affected the provinces of Zhejiang and Jiangsu before entering the Yellow Sea, crossing South Korea, and finally transitioning into an extratropical cyclone.

Typhoon Abe killed 108–195 people after it caused flooding and landslides in the Philippines and Taiwan, ravaged coastal areas of China, and brought high waves to Japan. Abe, which is responsible for killing 108 in China, affected half of Zhejiang's land area and a fourth of its population, leaving thousands homeless and causing ¥3.5 billion yuan (RMB, $741.5–743 million USD) to be lost in damages. Additional damage and one fatality occurred in Okinawa Prefecture in Japan, where at least ¥890 million yen (JPY, US$6 million) in damage was caused.

Typhoon Becky (Heling)

Tropical Storm Becky, having developed on August 20, hit northern Luzon on the 26th as a strong tropical storm. It strengthened over the South China Sea to an 80 mph typhoon, and hit northern Vietnam at that intensity on the 29th. The lowest station pressure measured at a weather station in Ba Đồn on August 29 was 987.0 hPa. Becky was responsible for killing 32 people and causing heavy flooding.

Tropical Depression Cecil

Cecil hit China. Despite being weak, Cecil caused intense flooding. Numerous homes were inundated and landslides were reported. 42 people were killed.

Typhoon Dot (Loleng)

Typhoon Dot formed from a monsoon trough to the southwest of Guam. Dot moved steadily towards the northwest and strengthened into a typhoon. Typhoon Dot reached peak intensity of 85 mph before weakening slight before landfall on eastern Taiwan on 7 September. After passing Taiwan Dot regained typhoon intensity in the Formosa Strait before making a final landfall in Fujian Province, China. On northern Luzon Island rains from Typhoon Dot caused floods killing 4 people, on Taiwan 7 people died. Losses in Taiwan reached NT$730 million (US$27.1 million). Dot caused heavy flooding in China. 74 people were killed and losses reached 1.02 billion RMB (US$216 million).

Typhoon Ed (Miding)

Severe flooding produced by the storm killed at least 18 people in Vietnam. At least 4,500 homes were destroyed and another 140,000 were inundated.

Typhoon Flo (Norming)