The 1970 Pacific hurricane season was an active Northern hemisphere hurricane season, especially during its early months. It officially started on May 15, 1970, in the eastern Pacific Ocean, and on June 1, 1970 in the central Pacific. It ended on November 30, 1970 in both regions. These dates conventionally delimit the period of each year when most tropical cyclogenesis occurs in these parts of the Pacific.

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.