Should I bring a raincoat to Hawaii? Maybe. If you'll be spending a lot of time on the windward sides of the islands (including Hawaii Volcanoes National Park on the Big Island) a packable rain jacket will come in handy.
Does it get cold in Hawaii?
It does not have the extremes of cold winters and summer heat waves and it usually does not have hurricanes and hailstorms. However, Hawaii's tallest peaks do get their share of winter blizzards, ice, and snow. Highest temperatures may reach into the 90s.
Does it get cold at night in Hawaii?
Daytime temperatures reach well into the 80s and even the lower 90s in some locations, especially the drier leeward sides. Overnight low temperatures are in the 70s. At higher elevations, such as Haleakala on Maui and Mauna Kea and Mauna Loa on the Big Island, temperatures are much cooler.