In November 1964, the quick succession of three typhoons—Iris, Joan, and Kate—caused widespread flooding in Vietnam. Constituting part of a very active typhoon season, the three typhoons made landfalls in South Vietnam within a 12-day period. The floods occurred against the backdrop of the escalating Vietnam War. Hardest-hit were the central provinces of South Vietnam where the storms moved ashore. Approximately 7,000 people were killed and over a million people were displaced by the storms as floods inundated over 20,000 km2 (7,500 mi2) of land. An estimated 54,000 homes were destroyed.

The 1964 Pacific typhoon season was the most active tropical cyclone season recorded globally, with a total of 39 tropical storms forming. It had no official bounds; it ran year-round in 1964, 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.