The Hawaiian Islands are a natural playground with endless snorkeling, kayaking, stand up paddle boarding, zip lining, and volcano exploration. Plus wildlife encounters with sea turtles, manta rays, whales and dolphins.
The average temperature is between 75˚–85˚ F (24˚-29˚ C) with summer (between April and November) being a little warmer and drier, and winter (between December and March) a bit cooler – but nothing like over on mainland USA!
Not having travel insurance on an overseas trip (or domestic) is not worth the risk. Anything can, will, and sometimes does go wrong. If it does and you are not insured, you can be up for a lot of money AND inconvenience.