Weather in Hiroshima in May

A good month. May is a solid month to be in Hiroshima. Highs average 24 °C, lows 13.2 °C, and rain falls on 10 days — nothing in the month is working against you.

May ranks 2 of 12 in Hiroshima. Only October scores clearly higher, and the difference is small enough to be settled by price rather than weather.

The rain arrives in bursts — 5 of the 10 wet days are heavy ones. Mornings tend to hold; build the outdoor half of each day before lunch and keep the afternoon flexible. 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. Across the twenty years measured, the hottest May day reached 33.3 °C and the coldest night fell to 4.4 °C, and the wettest single day dropped 98 mm — roughly 67% of the month's rain in one day.

May is moderately variable: 41 mm in the driest year against 342 mm in the wettest, around an average of 146 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 7 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 79%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way up: 4.7 °C warmer than April, and June adds another 3.4 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in May

May is at or near the longest days of Hiroshima's year: 13.9 hours of daylight, gaining 0.8 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

Sea temperature

The sea sits at about 17 °C in May — cold — a quick dip rather than a swim, and a wetsuit if you are in for longer. The sea peaks at 26.9 °C in August and bottoms out at 12.9 °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, June is the trade worth considering — 13 points weaker on weather, and materially quieter.

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

May in Hiroshima versus nearby

If Hiroshima is one option among several, the nearby comparison is worth making. Kitakyushu is close enough to be a coin toss — 2.9 °C cooler, the same number of rain days. Fukuoka is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: May is effectively as good as it gets here — 3 points behind October, which is inside the margin where the weather stops being the deciding factor and price starts being it.

Every month in Hiroshima

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