1. Honokohau Battle: On January 15, 1782, a battle occurred between the forces of Kalani'opu'u and a rival chief named Keōua Kuahuula. This battle, known as the Honokohau Battle, is considered one of the bloodiest in Hawaiian history.

2. Hawaiian Flag Day: January 15 is celebrated as "Hawaiian Flag Day" to honor the day in 1794 when the flag of the Kingdom of Hawaii was first flown.

3. Duke Kahanamoku's birthday: Duke Kahanamoku, a legendary surfer and Olympic medalist, was born on January 15, 1890, in Honolulu. Today, he is regarded as the "father of modern surfing."

4. Pearl Harbor Attack Commemoration: On January 15, 1998, a commemoration ceremony was held to mark the 57th anniversary of the attack on Pearl Harbor. The USS Arizona Memorial was rededicated during this ceremony.

5. Women's March: On January 15, 2017, thousands of people in Hawaii joined the Women's March, a global movement protesting the inauguration of Donald Trump as the 45th president of the United States. The march was one of the largest in the state's history.