Weather in Busan in September

A good month. September works. It is not the peak, but nothing about it fights you. Highs average 25.1 °C, lows 19.8 °C, and rain falls on 11 days — nothing in the month is working against you.

September ranks 4 of 12 in Busan: past the worst of the year but short of October, which is the month to book if the dates are open.

The rain arrives in bursts — 5 of the 11 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 September reaches 30 °C; the day barely swings — 5.3 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest September day reached 30.1 °C and the coldest night fell to 12.9 °C, and the wettest single day dropped 134 mm — roughly 77% of the month's rain in one day.

September is moderately variable: 37 mm in the driest year against 385 mm in the wettest, around an average of 175 mm. Roughly two Septembers in three land near that average, and the third does something else entirely.

Wind is light at 13.1 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 82%, high enough to notice on the warm days without dominating them.

How September sits in the year

The month is on the way down: 3.4 °C cooler than August, with October dropping another 4.5 °C. The first week and the last are not the same trip. Rain is the thing that moves: October brings 6 days less of it, so pushing the dates later buys drier weather.

Daylight in September

12.4 hours of daylight, losing 1.1 hours across the month. That is between Busan's extremes of 14.5 and 9.8 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 25.2 °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. September is the value pick for Busan: it scores within 14 points of October without carrying October's prices.

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

September in Busan versus nearby

If Busan is one option among several, the nearby comparison is worth making. Daegu is close enough to be a coin toss — within a degree on temperature, the same number of rain days. Gwangju is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: September works, with October the better month by 14 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Busan

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