Weather in Honolulu in May

Prime time. If you get to pick your dates, May is the one. Highs average 26.8 °C, lows 23.6 °C, and rain falls on 11 days — nothing in the month is working against you.

Honolulu barely has seasons. May scores 81 out of 100 against a best of 81 in May — a gap small enough that the month you choose matters far less here than the week you choose.

Rain on 11 days, 1 of them heavy. Enough to need a plan B, not enough to need a plan around it. Nothing specialised needed — this is the month you pack for the trip rather than for the weather.

What the averages hide

Averages flatten a month, and this one hides a few things: it never really gets hot: not one day in an average May reaches 30 °C; the day barely swings — 3.2 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest May day reached 29.3 °C and the coldest night fell to 20.5 °C, and the wettest single day dropped 39 mm — roughly 85% of the month's rain in one day.

May is moderately variable: 6 mm in the driest year against 129 mm in the wettest, around an average of 46 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind sits around 18.3 km/h — a steady breeze rather than a nuisance, and welcome on the warmer days, and humidity is unremarkable at 74%.

How May sits in the year

Temperatures hold steady either side: 25.7 °C in April, 26.8 here, 27.5 in June. Nothing about the timing within the month matters much.

Daylight in May

May is at or near the longest days of Honolulu's year: 13.1 hours of daylight, gaining 0.4 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

Sea temperature

The sea sits at about 24.7 °C in May — warm enough to stay in as long as you like. The sea peaks at 26.6 °C in September and bottoms out at 23.7 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead. If the dates are flexible, February is the trade worth considering — 5 points weaker on weather, and materially quieter.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

May in Honolulu versus nearby

Honolulu has no close neighbour worth comparing against, so the useful question is how May there compares with May elsewhere. San Francisco in May is a different proposition entirely — 7.2 °C cooler, and the easier month overall — 19.6 °C and rain on 3 days, against 26.8 °C and 11 here. San Jose in May is a clearly better month — 23.6 °C and rain on 3 days, against 26.8 °C and 11 here.

So: May is the answer for Honolulu. If it is booked out or priced out, January is the next best thing at 1 points behind, and October is the month to keep off the shortlist.

Every month in Honolulu

See all twelve months in Honolulu, or where else to go in May.