How's the Weather?
Summers are hot and humid. Winters are cold and dry. Springs have cherry blossoms and pollution. Fall brings clear skies and colorful foliage.
However, two weather phenomena spice up the hot and cold seasons.
In the summer, the East Asia Monsoonal flow swipes warm air from the Pacific and tosses a moisture blanket on the peninsula.
In winter, Siberian winds descend and plop extra ice cubes in Korea’s glass.
Glance at the precipitation averages. You’ll see that most of Korea’s rain comes in the months of June and August.
Korea’s rainfall habits echo England or France. Gray clouds invade the skies and drizzle falls in twenty-four-hour chunks. Unless there’s a typhoon, you won’t find much lightning and thunder, or quick thirty-minute downpours.
It isn’t the end of days if rain encroaches on your bike trip. With preparation and waterproofing, you can squeeze in a pleasant ride.
How do you check the weather? The Korean government’s website provides a simple English language breakdown of the current and future weather. (The Korean language site offers the same info in a slicker package.)
Google offers a simple weather check. Give them spy privileges and search “How’s the weather?” They’ll use your phone’s GPS to pinpoint your location and give an accurate glance at the future.
Western weather sites pull from Korean weather agencies. So check your preferred resource.
Remember this made-up adage. For short rides, trust the weather like the family dog. For long rides, trust the weather like the people you vote for. Prepare for the worst.
South Korea is a small country. (Seven of them can fit in Texas). Climate doesn’t change much from region to region. But there are key differences.
In the winter, you’ll find snow and ice in the northeast. The Siberian winds cool the western coast more than the east.
In the summer, the Pacific warms the southern and eastern tips of the peninsula. Lots of folks flock to the beaches in Busan and Jeju Island.
Check out our season-by-season breakdown of the climate in South Korea.
Winter brings a special gift from the frozen tundras of Siberia. Cold Russian winds cross the Yellow Sea and suck moisture and warmth from the air.
Don’t think the conditions make riding impossible, though. There are three upsides to the cold. A) Blue skies and less rain. B) Reduced pollution. C) No crowds on the bike paths.
If you dress for the occasion and don’t mind naked trees, winter can bring some of the best rides of the year.
Want to find powder? Head north.
In Seoul, the Han River grows patches of ice. Smaller ponds freeze over. But the dry air doesn’t support heavy snowfall.
These scenic coastal roads see snow in January and February. But sun and road maintenance quickly clear icy conditions.
When snow comes down heavy, road maintenance crews put bike paths and country roads last on the list. This might lead to unavoidable patches or ice or snow. This equals danger for both thin road tires or thick MTB tires with mighty tread.
Our first recommendation, walk over the icy bits. Don’t want to slow down? Okay. Then let a few PSI (pounds per square inch) out of your tires. This puts more rubber on the road. And more rubber equals more traction.
Want to avoid snow? Head south. It rarely sticks in Busan (부산) and Ulsan (울산). In fact, Hyundai and Samsung located factories and shipyards there to avoid weather delays.
Heading further south, a few hundred kilometers off the southwest coast of the peninsula, you’ll discover Jeju Island. Korean’s refer to it as their Hawaii.
The island brings tropical flavors in the summer. But it isn’t the South Pacific in winter. Average January lows hit 3 °C (38 °F).
However, snow doesn’t pop up in Jeju’s forecast much. To see white powder, you must hike to the top of Hallasan Mountain (한라산).
What’s the most important piece of winter clothing? Jacket? Hat? Put on a t-shirt and shorts and bike around in January. With your blood pumping, your head and arms may last half an hour. But your fingers will cease to function in a minute.
Wear gloves. In winter, bring a good pair. The more wind blocked the better.
In fact, make sure all your outer layers can ward off the invisible enemy. A simple rain jacket over a few insulating layers could be enough to keep you toasty.
Remember, exercise makes heat. So keep layers light. Pillow thick layers restrict movement and soak up sweat. Synthetic workout shirts keep heat in and dry out fast.
Also, beware the chain monster! You’re looking for trouble if you ride around wearing loose khakis. Bike chains feed on pant legs.
You don’t need compression pants, though. A pair of wind-resistant slacks that hug your ankles will do.
Spring brings life back to Korea. The air softens. The temps warm. Scattered rain showers help trees fill their branches with white and green buds.
Winter’s icy fingers reach into early March and claim a few days. But by mid-April, a light jacket may be all you need when heading out on a ride.
Peak cherry blossom season only lasts a few days. But if you start at a lower latitude, you can chase their emergence north.
Jeju Island reaches full blossom towards the end of March. The cherry blossom trees in Seoul and Chuncheon fill with white around mid-April.
In springtime, warmth rides back into town to fanfare. But the outlaws pollution and smog bring up the rear and end the parade fast.
Who’s to blame for the bad air?
The second musketeer: the world’s second largest economy. China’s belching factories don’t just choke their own citizens. Their byproducts hitch a ride on the seasonal winds and cross into Korea.
Completing the triumvirate, Korea’s own success. The nation still relies on coal to power their industries. Like China, they dug themselves out of poverty with manufacturing, chemical processing, and oil and gas refinement.
Korea doesn’t have pea soup fog. But pollution in manufacturing hotspots may affect sensitive lungs. So take a few precautions.
First, download a smartphone pollution app. The Plume Air Report and AirVisual apps take forecasts from local governments and give you an AQI (Air Quality Index). Their simple color coded system warns when it’s time to stay indoors or put on a mask.
Covid-19 made the N95 face mask a part of the popular lexicon. The “95” in N95 refers to the amount of particulate matter masks can filter. Can you guess the percentage? 95%. Now, try to guess how much particulate an N99 mask filters.
Korea also produces KF masks. What does KF mean? Korean Filter. The name is the only difference between an N95. The number means the same thing.
If there isn’t a pandemic on, you can find N95 masks at any drugstore (약국) for about ₩3,000.
Though not as effective, reusable masks help block pollution. Apparel companies make comfortable, sports-focused masks.
Wash them at night and have a fresh lung shield for the next day’s ride.
Early March in Korea feels winter with notes of spring. You’ll regret leaving home without a light jacket and pants. At night, the frost monster hunts for exposed hands.
April brings more t-shirt days. However, bring something warm for your arms if you plan to ride past sundown.
The East Asia Monsoonal flow originates in warm Pacific waters. When summer rolls around, it invades Korea and turns the thermostat up to 11. More rain. More heat. More humidity.
Don’t let these elements scare you off. Like winter, a little preparation will make your ride enjoyable. Besides, you don’t want to miss prime time on the East Coast Bike Paths’ endless beaches.
Watch Out! Water!
Summer is the official monsoon season in Korea. If you glance at the precipitation chart, you’ll see July and August hold double the rainfall of all the other seasons combined.
When you glance at the forecast, you’ll see blocks of rain clouding two or three day chunks. On these days, gray skies cover and light to heavy rain drizzles all day. No sun.
Though rain may seem to track your every movement in summer, thunderstorms aren’t common. This means the only thing to fear on rainy days is water itself. Unless …
Mighty typhoons (hurricanes) stir around August and September. One or two thumpers cross Korea’s shores, putting emergency drills into practice.
But when a storm’s a brewin’, stay off your bike. Skies open. Rivers breach their banks. Wind tears down infrastructure. Imagine you on your 9 kilogram (20 pound) bike.
Watch Out! Sun!
After the rain, the sun comes. And it brings the heat.
The Korean summer isn’t a heavyweight like Iraq (48 °C; 120 °F). But don’t forget. It’s not the heat. It’s the humidity.
The East Asia Monsoonal flow stuffs the air with moisture. If you’re not careful, the one-two punch of sun and humidity can sap your energy, drain your fluids, and leave you on heat stroke’s doorstep.
Watch Out! Sun!
Fair skin? Wear sunscreen. Breezy bike rides give you radiation amnesia. Though your skin feels cool, the sun’s reactor constantly bombards your arms, legs, and face with rays.
In fact, bring sunscreen all-year long. Seasons come and go. The sun sticks around.
Summer’s a wet, hot mess. Even if the forecast doesn’t mention rain, prepare for it. If you see a forty percent chance, the meteorologist is saying, “maybe no rain. Or not. Your guess is as good as mine.”
Bring breathable shorts and t-shirts. A rain jacket is optional. Sometimes a sprinkle in 32 °C (90 °F) heat feels like a gift.
If you carry a backpack or panniers, bring a rain cover. This will keep your clothes and luggage dry.
Fall in Korea brings the best riding weather. Heat mellows. Rain abates. Even trees dress for the occasion.
Spring and fall mirror each other in Korea. Vivid oranges and reds replace springtime cherry blossoms. Cool air follows the river currents. And jacket temps return at night.
Unlike spring, though, you don’t need a facemask. Fall skies radiate blue and clean air rattle leaves.
September is diet-summer. Remnants of typhoon season bring a few drizzly days. But many of the days hold warmth. This makes it one of the best months to ride.
By October, the air grows crisp. Leaves turn. In the countryside, breathe deep and smell the woody scent from farmers burning their fields after harvest.
In November, winter’s fingertips grab hold. Trees bald. Burnt colored leaves cover bike paths.
The leaves in Korea run in reverse to the cherry blossoms’ path.
In Seoul, trees flush with color starting mid-October. When November comes, oranges and reds meander down to Busan. The trees of Jeju Island become the last to change in mid-November.
Like cherry blossom festivals, the changing leaves bring out festivals in the cities. Like in the west, people flock to national parks. Mountains reward hikers with glorious sights.
Holidays Arrive Early
Chuseok brings every family out of their apartment buildings and onto the highways and railroads. For three to five days in mid-September, transportation infrastructure swells to capacity.
Train tickets go faster than Coachella. Even if you grab a ticket, buses move slower than snails pulling a dog sled. You ain’t going not nowhere.
Fall is the most forgiving season in Korea. Day brings plenty of sunshine.
In early September heat, t-shirts and shorts cool you off. However, nighttime can bring a chill. Pack a light jacket.
As October and November approach, switch to longer shirts and pants (ankle huggers).
In November, the frost monster hunts for digits at night. Bring gloves, a skull cap, and an extra jacket.
Don’t forget the sunscreen. Even if it’s cold, the sun doesn’t take a break.