Hawaii Weather in May: May is one of the sunnier and drier months of the year, and temperatures continue to heat up. (Average highs 28ºC, average rainfall 43mm, Honolulu average water temperature 26ºC.) Hawaii Weather in July: High temperatures hold steady in July, with a little more rain than in June.Click to see full answer. Also question is, is it a good time to go to Hawaii in May?The best time to visit Hawaii is during May when many snowbirds have retreated, and the weather is pleasant, without the threat of hurricanes or excessive rainfall. May is also the tail-end of humpback whale-watching season.Additionally, what season is it in Hawaii in May? Weather in The Hawaiian Islands is very consistent, with only minor changes in temperature throughout the year. There are really only two seasons in Hawaii: summer (kau) from May to October and winter (hooilo) from November to April. Regarding this, how hot is Hawaii in May? May’s weather is usually quite nice. Daytime high temperature average in the low to mid 80s F. Nighttime temperatures only dip into the lower 70s F. The average ocean temperature starts to warm up in May and is certainly pleasant enough for swimming.Is it humid in Hawaii in May?When it has absorbed as much as it possibly can, humidity is 100 percent. Average humidity in Hawaii is highest in the morning and decreases as the day wears on.