The 1981 Pacific hurricane season was a slightly below average Pacific hurricane season. The season officially started on May 15 in the eastern Pacific basin and June 1 in the central Pacific basin. Both basins' seasons ended on November 30; these dates conventionally delimit the period during which most tropical cyclones form in the northeastern Pacific Ocean. The first tropical cyclone of the season was designated on May 30, and the final storm of the season, Hurricane Otis, dissipated on October 30. The season produced fifteen named storms and a total of eight hurricanes, which was near normal. However, the total of one major hurricane was below the average of three.

A Pacific hurricane is a tropical cyclone that develops within the northeastern and central Pacific Ocean to the east of 180°W, north of the equator. For tropical cyclone warning purposes, the northern Pacific is divided into three regions: the eastern, central, and western, while the southern Pacific is divided into 2 sections, the Australian region and the southern Pacific basin between 160°E and 120°W. Identical phenomena in the western north Pacific are called typhoons. This separation between the two basins has a practical convenience, however, as tropical cyclones rarely form in the central north Pacific due to high vertical wind shear, and few cross the dateline.