Triple-A updates its average prices every night by electronically harvesting the last credit card transaction of the night at gas stations in thousands of U.S. cities including three in Hawaii - Honolulu, Hilo and Wailuku.
Honolulu has been falling a penny a day, or most days, for several weeks, it's down 21 cents in the past month, and this morning it hit three dollars a gallon. A year ago it was $4.26.
Neighbor island prices fall more slowly because there is less competition, especially for interisland distribution to individual stations. Hilo has only fallen seven cents, and Wailuku only one cent, in the past month.