Hurricane Iwa, taken from the Hawaiian language name for the frigatebird, was at the time the costliest hurricane to affect the state of Hawaiʻi. Iwa was the twenty-third tropical storm and the twelfth and final hurricane of the 1982 Pacific hurricane season. It developed from an active trough of low pressure near the equator on November 19. The storm moved erratically northward until becoming a hurricane on November 23 when it began accelerating to the northeast in response to strong upper-level flow from the north. Iwa passed within 25 miles of the island of Kauaʻi with peak winds of 90 mph (140 km/h) on November 23, and the next day it became extratropical to the northeast of the state.

The 1982 Pacific hurricane season was, at the time, the most active Pacific hurricane season on record, with 23 named storms. Of those, 12 became hurricanes, with 5 intensifying into major hurricanes. The season officially started on May 15 in the eastern Pacific basin and June 1 in the central Pacific basin. The season in both basins ended on November 30. These dates conventionally delimit the period during which most tropical cyclones form in these regions of the Pacific Ocean. The first tropical cyclone of the season, Tropical Storm Aletta, formed on May 20, and the final one of the season, Hurricane Iwa, dissipated on November 25. A strengthening El Niño that year fueled the season's above normal activity.