Almost every month in Hawaii comes with a trade you have to accept. Winter buys you whales and charges you rain and swell. Summer buys you calm water and charges you the crowd and the rate. September buys you quiet and asks you to gamble slightly on a storm.
May does not really have one, and that is the whole page.
What you get
Dry season weather. May is properly into it, with far fewer wet days than any month from November to March, and the windward and leeward gap narrower than it is all winter.
Every coast swimmable. The north Pacific swell has gone. Beaches on Oʻahu's north shore, Maui's north coast and Kauaʻi's north end are places you can get in the water rather than places you photograph. That is a much bigger island than the winter version.
Warm enough water. High seventies and climbing. A rash guard is a preference by now, not a fix.
Shoulder pricing. This is the part people miss. Summer rates start in June with the school holidays, so May is the last month of the cheaper half of the year with none of the weather that usually comes with it.
What you do not get
Whales. They have gone. If humpbacks are the reason for the trip you want February, and no amount of good weather in May substitutes for it.
The very biggest surf. Not a loss for most people, but if watching serious north shore waves was on the list, that is a winter trip.
That is close to the whole list, which is unusual.
Memorial Day is the one busy week
The last weekend of May is a mainland holiday and rates and crowds move for roughly that week. It is a bump rather than a Christmas-scale spike, and the rest of the month is unaffected.
If your dates are flexible, the first three weeks are the ones to take. Early May in particular is quiet, because the spring break traffic has long gone and the summer traffic has not started.
What this month is actually good for
The things winter closes. Hiking is comfortable and the trails have dried out from the wet season without turning to dust. Snorkeling works on coasts that were unusable in February. Boat trips run with far fewer weather cancellations than they do from December to March.
It is also the best month for a first Hawaii trip, because nothing is fighting you: the weather is reliable, everything is open, and you are not planning around swell or rain.
Is May a good month?
It is the best all-round month of the year, and if your dates are genuinely open this is the answer. The reason it is not obvious is that May has no headline: no whales, no holidays, nothing to build a marketing campaign on. It is simply good, everywhere, at a fair price.
Late April is the close relative and slightly cheaper. September is the other quiet month and warmer in the water. The month-by-month comparison puts all three side by side.
Check the live numbers
Every month, side by side, is on the Hawaii weather reference: monthly rainfall for five stations plus sea temperature, taken from NOAA. The figures on this page describe a typical year. For the one you are actually travelling in:
- Water temperature, NOAA station 1612340. Live and historic readings from Honolulu Harbor. The monthly averages quoted here are the 34,802 hourly observations, 2021 to 2024 mean from this station.
- National Weather Service, Honolulu. Forecasts and warnings for every island, including the high surf advisories that decide which coasts are swimmable this week.
- National Hurricane Center. Worth a look in the week before you fly between June and November, and worth ignoring the rest of the year.
