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.

The 1957 Pacific hurricane season was a moderately active year in which 13 tropical cyclones formed. The hurricane season ran through the summer and fall months which conventionally delimit the period during which most tropical cyclones form in the northeastern Pacific Ocean. The first tropical cyclone developed on July 15. The final storm dissipated on December 6, becoming one of the few Pacific storms to exist outside of the seasonal dates. Of the season's 13 storms, five of these formed or crossed into the central Pacific.