The 1975 Pacific typhoon season was one of the most deadliest tropical cyclone seasons on record, with nearly 230,000 fatalities occurring during the season. It had no official bounds; it ran year-round in 1975, but most tropical cyclones tend to form in the northwestern Pacific Ocean between June and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean.
Some of the notable storms here are Typhoon Nina, which caused the Banquiao Dam flood, which resulted in approximately 229,000 people dead, and Super Typhoon June, which was the strongest storm on record with a pressure of 875 mbar, until beaten by Typhoon Tip in 1979 with 870 mbar.
Typhoon Lola (Auring) was a very early typhoon. It made landfall on Mindanao as a minimal typhoon on January 24 and transversed the southern Philippines as a tropical storm. Lola crossed the South China Sea before stalling in the open sea and dissipating on January 28. The typhoon caused 30 casualties from mudslides and heavy rain.
Nina was a short-lived but rapidly intensifying typhoon. After forming on July 30, it struck Taiwan at super typhoon intensity. It stayed a typhoon during its passage over the island, causing 25 fatalities and widespread damage. It emerged into the Formosa Strait and weakened to a tropical storm. Nina headed inland. Its moisture interacted with a cold front, causing a huge amount of rainfall. The rainfall contributed to the bursting of the Banqiao Dam, causing the deaths of around 200,000 people.
Phyllis struck the southern part of Japan on August 17 as a minimal typhoon, having weakened from a peak of 140 mph winds. Phyllis caused over 60 casualties, with landslides and flooding causing moderate to heavy damage.
Rita formed August 17 and erratically headed north and affected the Ryūkyū Islands. Rita then made landfall on Shikoku as a moderately strong Category 1 typhoon. It moved along the entire length of Japan, weakening to a depression. Rita strengthened back into a tropical storm over the Kuril Islands— an unusually northerly location— before dissipating on August 24. At least 26 deaths can be attributed to this typhoon from the heavy flooding— the worst in 10 years.
Typhoon June was the strongest storm of the season, but it had no effect on land. At the time, June was the strongest typhoon on record, and tropical cyclone worldwide, with a minimum central pressure of 875 millibars. June was also the first recorded case of a typhoon with triple eyewalls.