Weather in Seoul in May

Prime time. May is about as good as Seoul gets. Highs average 21.5 °C, lows 11 °C, and rain falls on 8 days — nothing in the month is working against you.

May is the highest-scoring month of the twelve. The nearest rival is October, and the month at the other end of the year is December.

Rain on 8 days, 3 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. Across the twenty years measured, the hottest May day reached 28.9 °C and the coldest night fell to 4.2 °C, and the wettest single day dropped 83 mm — roughly 99% of the month's rain in one day.

May is moderately variable: 19 mm in the driest year against 139 mm in the wettest, around an average of 84 mm. Roughly two Mays in three land near that average, and the third does something else entirely.

Wind is light at 9.9 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 75%, high enough to notice on the warm days without dominating them.

How May sits in the year

The month is on the way up: 5.9 °C warmer than April, and June adds another 4.3 °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 Seoul's year: 14.2 hours of daylight, gaining 0.8 hours across the month. Evenings are the real gain — dinner outdoors still happens in full light.

An inland climate

With no coast nearby, the year swings a fair way — 35.2 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Peak season. Expect the highest prices of the year and to be booking well ahead.

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

May in Seoul versus nearby

If Seoul is one option among several, the nearby comparison is worth making. Daegu is close enough to be a coin toss — 3.2 °C warmer, the same number of rain days. Gwangju is close enough to be a coin toss — within a degree on temperature, the same number of rain days.

So: May is the answer for Seoul. If it is booked out or priced out, October is the next best thing at 0 points behind, and December is the month to keep off the shortlist.

Every month in Seoul

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