Vietnamese Summer Rolls

In Hawaii, eating Vietnamese Spring Rolls are called Summer Rolls, so when I want an Imperial Roll I need to ask for a Spring Roll and when I want a Spring Roll I need to order a Summer Roll. Confused? I wonder where Hawaii picked up the term Summer Rolls anyway? All the other major cities in the U.S. (e.g. D.C., Boston, LA and New York) use the same terminology. I wonder why it's different in Hawaii?

Clockwise from Top Left: Hawaii Summer Roll, Hawaii Spring Roll, Mainland Spring Roll, Mainland Imperial Roll (Culture Shock #79)