Why can summer travel in Korea be tiring? Humidity, warm nights, and summer rain
Summer in Seoul means considering humidity, warm nights, and concentrated seasonal rainfall as well as daytime temperatures. Comparing climate normals for the same period in Seoul, Tokyo, and London helps explain why long walking days can be tiring and what you can enjoy in summer instead.
Why can summer travel in Korea be tiring? Humidity, warm nights, and summer rain
Yanghwa-ro in Seoul at night, with a rain-wet road, August 2020.
Walking through palace courtyards and neighborhood lanes, exploring a market, then heading to a park: a day that's enjoyable in spring or autumn can feel much harder in Korea's midsummer. It isn't just the temperature; humidity and rain come with it. The Korea Tourism Organization describes summer as hot and humid and recommends the milder spring and autumn for walking trips.[1]
That doesn't mean Korea is hotter than every other country. What feels unfamiliar will depend on the summers you've experienced elsewhere. Comparing Seoul with Tokyo and a London weather station on the same basis makes the differences clearer.
Why the same temperature feels more tiring in humid weather
As sweat evaporates, it carries heat away from your body. High relative humidity slows evaporation, making it harder for your body to release heat. The US National Weather Service explains this difference through the heat index, which combines air temperature and relative humidity.[2] That's why the temperature alone isn't enough to judge whether a long walk will be comfortable.
Travel can mean spending a long time outdoors. Walking between sights, taking photos, and waiting to enter all add up. On a hot day, the time you actually spend outside can be more taxing than the number of places on your list.
People walking along Myeongdong 7-gil, August 2023.
Hotter than Tokyo? How different from London?
All the figures below are climate normals for 1991–2020. They are August's average daily maximum and minimum temperatures, each averaged across the month, not heatwave records or forecasts for your travel dates.[3][4][5]
• Seoul: average daily maximum 30.0℃, average daily minimum 22.9℃.[3]
• Tokyo: average daily maximum 31.3℃, average daily minimum 23.5℃.[4]
• London Heathrow station: average daily maximum 23.4℃, average daily minimum about 14.1℃.[5]
On this measure, Tokyo's temperatures are higher than Seoul's. It would therefore be wrong to say that Korea is always hotter than Japan in midsummer. Compared with London Heathrow, however, Seoul has higher minimum temperatures as well as higher daytime temperatures. That can matter if you're used to a cool night after a hot day.
This comparison concerns temperatures at three observation sites. It doesn't represent the whole of Korea, Japan, or the UK, and it isn't a ranking of how hot they feel with humidity included. Even within Seoul, the heat outdoors varies with the date, location, sunshine, and wind.
Summer rain affects your plans too
For the same 1991–2020 period, July's normal monthly rainfall is 414.4mm in Seoul, 156.2mm in Tokyo, and 45.8mm at London Heathrow.[3][4][5] For this month, at least, Seoul's summer rainfall is on a different scale from the other two sites.
A high monthly rainfall total doesn't mean it rains for the same length of time every day. The Korea Tourism Organization recommends following forecasts with the rainy season in mind for trips between late June and late July, but the dates when the rains begin and end vary each year.[1] For your actual travel dates, look at the forecast for the area you'll visit.[6]
Rain can lead to restrictions at outdoor sites, not just a need for an umbrella. If there are heavy-rain or strong-wind notices, or riverside areas and walking paths are closed, follow the on-site instructions rather than entering on your own because the rain has eased.
What you can still enjoy in summer
The Korea Tourism Organization suggests summer for travelers who want beaches and water activities.[1] If the sea is the reason for your trip, summer has its appeal. But walking on a beach and swimming are different activities. Before entering the water, check that year's opening announcement and any swimming restrictions in effect that day.
In Seoul, you can combine a short palace visit with an indoor exhibition. Look at opening and palace-closure notices and the day's weather first; if it's already hot in the morning, postpone or shorten the outdoor visit. The National Museum of Korea is an indoor destination for art and cultural artifacts, but it also has outdoor spaces, so focus on the indoor exhibitions if you're going to get out of the rain.[7] Its official visitor information covers exhibition reservations and closing days.
If the rain is light and it's safe to get around, you could follow an exhibition with a meal nearby or visits to cafés, cinemas, and shops. If weather warnings or restrictions make the journey itself dangerous, postpone setting out even if your destination is indoors.
Consider spring or autumn if you want long walks outdoors, and summer if you'd like to combine beaches with indoor activities.[1] For clothing and packing, see what to wear in Korea; for indoor plans in Busan, see Busan on a rainy day; and for a visit to the river, see the Hangang park guide.
Sources
[1] Climate & Seasons: A Year-Round Travel Guide
[2] US National Weather Service: heat index and humidity
[4] Japan Meteorological Agency: 1991–2020 climate normals
[5] UK Met Office: Heathrow 1991–2020 averages
[6] Korea Meteorological Administration: short-range forecast
Photo credits
• Cover: Tony (Flickr: anileated) · Rain and Night in Yanghwa-ro.jpg · CC BY 2.0 · Orientation corrected, resized and JPEG re-encoded.
• Photo 1: SKTakek · Myeongdong-7gil-2023.jpg · CC0 1.0 · Orientation corrected, resized and JPEG re-encoded.