The 2003 Pacific typhoon season was a slightly below average yearlong period of tropical cyclogenesis exhibiting the development of 45 tropical depressions, of which 21 became named storms; of those, 14 became typhoons. Though every month with the exception of February and March featured tropical activity, most storms developed from May through October. During the season, tropical cyclones affected the Philippines, Japan, China, the Korean Peninsula, Indochina, and various islands in the western Pacific.

Typhoon Kujira, known in the Philippines as Typhoon Amang, was a long-lived tropical cyclone that lasted for 16 days and affected the island nations of Micronesia, Taiwan, and Japan in April 2003, as well as the earliest typhoon in a calendar year to ever make landfall on the latter. Forming from a broad area of disturbed weather as a tropical depression on April 9 well removed from any landmasses, Kujira quickly intensified in its early stages, and was upgraded to a tropical storm just two days after cyclogenesis. Strengthening slowed afterwards, though the storm attained typhoon intensity on April 14. Intensification continued and late on April 15, Kujira reached its peak intensity with winds of 165 km/h (103 mph) and a minimum barometric pressure of 930 mbar. Following peak intensity, Kujira began to track northwest and oscillate in strength, cresting an additional two times in intensity. On April 21, the typhoon was downgraded to tropical storm intensity and began to track erratically for several days east of Taiwan. However, on April 24, Kujira resumed a northward track and begin to weaken, and on April 24 was downgraded to tropical depression strength as it made landfall on Kyushu. Following landfall Kujira transitioned into an extratropical cyclone and continued to persist before these extratropical remnants crossed the International Dateline towards the end of April 2003.