Weather in Hiroshima in September

A good month. September works. It is not the peak, but nothing about it fights you. The heat itself is manageable at 28.1 °C, but 83% humidity is what you will actually feel.

September ranks 6 of 12 in Hiroshima: past the worst of the year but short of October, which is the month to book if the dates are open.

This is wet-season rain: 13 wet days and 5 genuinely heavy ones, which in this climate means concentrated downpours rather than all-day grey. The pattern is usually a clear morning and a loud afternoon, so front-load the day and stop fighting the 3pm hour. Natural fibres and a second shirt for the day. At 83% nothing dries, including you.

What the averages hide

Averages flatten a month, and this one hides a few things: 8 days top 30 °C — hot spells arrive, but they break. Across the twenty years measured, the hottest September day reached 36.8 °C and the coldest night fell to 9.7 °C, and the wettest single day dropped 105 mm — roughly 62% of the month's rain in one day.

September is moderately variable: 56 mm in the driest year against 426 mm in the wettest, around an average of 170 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 6.8 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 83%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.7 °C cooler than August, with October dropping another 5.3 °C. The first week and the last are not the same trip.

Daylight in September

12.4 hours of daylight, losing 1.1 hours across the month. That is between Hiroshima's extremes of 14.4 and 9.9 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 25.1 °C in September — warm enough to stay in as long as you like. This is the warmest the water gets all year.

How busy it gets

Shoulder. The value months — prices ease off and you get the place closer to itself.

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

September 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 — within a degree on temperature, 1 day more rain. Fukuoka is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: September works, with October the better month by 15 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Hiroshima

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