Seoul Weather by Month: What to Actually Pack (6 Years of Real Data, 2026)
Hongdae · Seoul · 6-Year Weather Record
Two weeks before your flight, you type “Seoul April weather” into a search bar. Every result tells you the same thing. “Average high 18°C. A light cardigan should be fine.” You believe it. You pack light. Then on April 7th, standing at Namsan at 7 AM waiting for the sunrise, your hands go numb inside your pockets. By 2 PM, you’re walking through Seongsu-dong with your jacket balled up under one arm, sweating through your T-shirt.
Averages don’t lie. They just don’t tell you the truth, either.
The short answer: Seoul’s April average high really is 17.9°C. But over the past six years, the same month has swung from an overnight low of −1.4°C to an afternoon high of 28.1°C — and a single April day averages an 11.3°C spread from morning to evening. Don’t pack for a monthly average. Pack for what actually happened on your exact travel dates over the last six years. The calculator below shows you exactly that.
🧳 Leave the bulky stuff at home 🌡️ Save your baggage for season-right clothes 📍 Grab the rest at Hongdae Station Exit 3
Every number in this article comes from six years of actual measured reanalysis data for central Seoul (lat 37.57 / lon 126.98), 2020 through 2025. Not “usually around this.” Not “most guidebooks say.” Real recorded highs and lows, day by day.
🧮 What Really Happened on Your Dates — The Last 6 Years
Pick your arrival and departure dates, and the tool compares daily highs and lows from 2020–2025 side by side. Up to 7 days at a time.
Loading weather data…
Open-Meteo ERA5 reanalysis (°C). Highs first, then lows. Feels-like temperature may differ.
How Averages Fool You
Here’s the thing about Seoul weather. It’s not the cold that trips people up. It’s not the heat either. It’s the swing.
Same date, different years: April 15th hit 26°C one year and barely scraped 12°C another. Both are real. The “April average high of 17.9°C” you see on every weather site is the midpoint of two experiences neither traveler actually had.
And within a single day? The swing is brutal.
| Season | Avg Daily Swing | What It Actually Means |
|---|---|---|
| March | 11.4°C | Winter morning, spring afternoon |
| April | 11.3°C | Cherry blossom photos at 7 AM? That’s 5°C. Dress for it. |
| May | 10.4°C | T-shirt by day, regret by sunset |
| Jul–Aug | 6.5–6.9°C | No relief at night — tropical nights |
| January | 8.8°C | Below freezing all day. The absolute cold is the problem, not the swing. |
The one rule that covers every season: Don’t pack one thick coat. Pack multiple layers you can take off. In spring and fall, you’ll move through 11°C of temperature in a single day. In summer, you’ll bounce between 29°C streets and 22°C cafés. Thickness isn’t your friend — number of layers is.
Spring (Mar–May) — Two Seasons in One Day
Early March is still winter. Across six years, March alone averages 14.5 nights below freezing. Meanwhile, late May has hit 29.5°C. That’s a 30-degree spread inside one word — “spring.”
| Month | Avg Low | Avg High | Recorded Extremes | Rainy Days | What to Pack |
|---|---|---|---|---|---|
| March | 0.6°C | 12.0°C | −8.3 ~ 22.9°C | ~7 days | Wool coat, knits, scarf |
| April | 6.5°C | 17.9°C | −1.4 ~ 28.1°C | ~6 days | Trench coat, cardigan, light knit |
| May | 11.7°C | 22.1°C | 4.7 ~ 29.5°C | ~9 days | T-shirts + cardigan, light shirt |
For cherry blossom travelers: The trap isn’t the afternoon — it’s the morning. You want crowd-free photos at Yeouido’s Yunjung-ro or Seokchon Lake? You need to be there by 7 AM. At that hour in April, the average temperature is 6.5°C — about 11 degrees colder than what you’ll feel at 3 PM. Wear the outfit you want in the photos, but bring a jacket you can shed and stuff in your bag the moment the sun climbs.
May is arguably the best outdoor month — but it’s also when rainfall climbs noticeably (124 mm on average, more than double March). If a Hangang picnic is on your itinerary, a foldable umbrella isn’t extra weight. It’s insurance.
🧳 Spring rentals that save your trip: Traveling with a child? A stroller from ₩15,000/day. Spring festivals mean a lot of walking, and nothing ruins a cherry blossom stroll faster than a stroller wheel that snapped off in the cargo hold. → Browse baby gear rentals
Summer (Jun–Aug) — It’s Not the Heat, It’s the Humidity (and the AC)
July and August share the same average high: 29.3°C. On a screen, that looks manageable. On the ground, three things make it feel very different.
First, the nights don’t cool down. The day-night gap shrinks to 6.5–6.9°C, the narrowest of the year. If it was 33°C at 3 PM, it’s still 26°C at 3 AM. That’s a tropical night, and Seoul gets plenty of them.
Second, the rain comes in bursts. July averages 309 mm. August, 332 mm. But the year-to-year spread is wild — July alone has gone from 130 mm to 522 mm since 2020. And it doesn’t drizzle all day. It dumps for an hour, then stops. A compact umbrella and fast-drying shoes beat a rain jacket every time.
Third, indoors is freezing. Subway cars, cafés, department stores, restaurants — summer interiors hover around 22°C. Walk around in a tank top all day and you’ll regret it by the second café stop.
| Month | Avg Low | Avg High | Recorded Extremes | Rainy Days | 30°C+ Days | What to Pack |
|---|---|---|---|---|---|---|
| June | 18.0°C | 27.1°C | 12.1 ~ 35.6°C | ~12 days | ~5 days | Short sleeves, light long pants, compact umbrella |
| July | 22.4°C | 29.3°C | 16.7 ~ 38.5°C | ~19 days | ~13 days | Breathable fabrics, hat, umbrella |
| August | 22.8°C | 29.3°C | 13.2 ~ 36.4°C | ~19 days | ~14 days | Linen/cotton, sandals, sunscreen |
The Seoul summer trio: A foldable umbrella, a thin cardigan (not for outside — for the indoor air conditioning), and shoes that dry fast. Leather sneakers surrender on day one in July. Heat-wave warnings cluster in late July and early August, so if you’re traveling then, leave 1–4 PM open in your outdoor itinerary.
💇 Summer humidity meets your hair: At 80% humidity, a hair tool in Seoul isn’t vanity — it’s survival gear. But here’s the catch: Korea runs on 220V / 60Hz. If you’re coming from the US (110V/60Hz) or Japan (100V), your device needs more than a plug adapter — it needs a voltage converter, and Dyson explicitly says not to use those. Even if you’re from Europe (230V/50Hz), the frequency jump from 50 to 60Hz makes motors spin 20% faster, overheating and shortening their life. And cordless hair tools with built-in batteries? Airlines are increasingly refusing them at both cabin and check-in. Renting locally is the safer, simpler bet. → Dyson rentals from ₩10,000/day
Fall (Sep–Nov) — Seoul at Its Most Beautiful, Until November Turns into Winter
Early September still feels like summer — average high 25.7°C, with a recorded peak of 32.7°C. Then mid-October arrives and suddenly the sky turns that deep, clear blue Seoul is famous for. By November, nights are dropping below zero — 10.5 sub-zero nights in an average November.
| Month | Avg Low | Avg High | Recorded Extremes | Rainy Days | What to Pack |
|---|---|---|---|---|---|
| September | 18.0°C | 25.7°C | 10.3 ~ 32.7°C | ~11 days | Summer clothes + light long-sleeve, umbrella |
| October | 9.6°C | 18.6°C | 0.4 ~ 26.7°C | ~8 days | Jacket, knit, light scarf |
| November | 2.3°C | 11.8°C | −9.0 ~ 23.0°C | ~6 days | Coat, Heattech, gloves |
October is the sweet spot. Rainfall drops to 89 mm, clear days stack up, and the foliage around Gyeongbokgung and Bukchon is at its peak. It’s hands-down the best month for outdoor plans. But here’s the warning: October and November have the steepest month-to-month drop of the entire year. The average high falls from 18.6°C to 11.8°C. The low goes from 9.6°C to 2.3°C. A trip starting October 28th and a trip starting November 12th are two completely different vacations.
Bringing your parents? Fall is the ideal season for it — no heat, no monsoon, beautiful everywhere. But Gyeongbokgung, Bukchon, and Changdeokgung’s Secret Garden involve way more walking than most people expect. A rollator (₩21,000/day~) or wheelchair (₩15,000/day~) isn’t about “needing” one — it’s about keeping everyone out together until dinner instead of heading back to the hotel by 2 PM. → Browse mobility rentals
Winter (Dec–Feb) — The Number on the Thermometer Isn’t the Real Story
January: average high 2.4°C, average low −6.4°C. The six-year record low: −18.8°C. And roughly 29 out of 31 January nights dip below freezing. Practically every night.
| Month | Avg Low | Avg High | Recorded Extremes | Sub-Zero Nights | What to Pack |
|---|---|---|---|---|---|
| December | −5.5°C | 2.8°C | −17.5 ~ 15.6°C | ~28 nights | Padded jacket, Heattech, gloves, beanie |
| January | −6.4°C | 2.4°C | −18.8 ~ 11.1°C | ~29 nights | Long padded coat, thermal base layer, scarf, hand warmers |
| February | −4.6°C | 5.1°C | −13.7 ~ 16.3°C | ~25 nights | Padded jacket, knit, gloves |
The temperature alone is one thing. The wind is what gets you. Open spaces — the Han River banks, Gwanghwamun Square, the plaza around Lotte World Tower — make the air feel 5 to 8 degrees colder than the thermometer says. A displayed −6°C can feel like −13°C when you’re standing on an exposed bridge.
The Seoul winter three-layer formula: ① A thermal base layer (Heattech or similar) ② A knit or fleece mid-layer ③ A windproof padded jacket. Then add gloves, a scarf, and a beanie. This is the mistake travelers from Europe and North America make most often — thinking one heavy coat is enough. It’s not. The thermal base layer takes up almost no suitcase space. Bring it.
December and January are the driest months — only 26–27 mm of rain. Snow happens but rarely enough to disrupt travel. What you should actually worry about is ice on the sidewalks. Snow melts during the day and freezes overnight into slick, invisible patches. Shoes with real grip matter more than you’d think.
🧥 The winter luggage dilemma: A long padded coat is the single bulkiest thing you’ll pack. But you can’t rent it — you have to bring it or wear it onto the plane. So here’s the strategy: rent everything else that’s bulky. Travel cot (₩15,000/day~), garment steamer (₩5,000/day~), portable screen (₩35,000/day~). Even with a coat eating half your suitcase, your bag will still close. → Browse all rentals
At a Glance — All 12 Months (2020–2025)
| Month | Avg Low | Avg High | Rainfall | Rainy Days | One Line |
|---|---|---|---|---|---|
| Jan | −6.4°C | 2.4°C | 27mm | 4 days | Coldest. Three layers mandatory. |
| Feb | −4.6°C | 5.1°C | 24mm | 5 days | Still winter. Eases by month’s end. |
| Mar | 0.6°C | 12.0°C | 51mm | 7 days | Winter mornings, spring afternoons. |
| Apr | 6.5°C | 17.9°C | 65mm | 6 days | Cherry blossoms. Beware the 7 AM freeze. |
| May | 11.7°C | 22.1°C | 124mm | 9 days | Best outdoor month. Rain increasing. |
| Jun | 18.0°C | 27.1°C | 164mm | 12 days | Monsoon begins. |
| Jul | 22.4°C | 29.3°C | 309mm | 19 days | Wettest. Record high 38.5°C. |
| Aug | 22.8°C | 29.3°C | 332mm | 19 days | Most rain. Tropical nights. |
| Sep | 18.0°C | 25.7°C | 215mm | 11 days | Early month = summer. Late = fall. |
| Oct | 9.6°C | 18.6°C | 89mm | 8 days | Best month of the year. |
| Nov | 2.3°C | 11.8°C | 58mm | 6 days | Second half is winter. Pack accordingly. |
| Dec | −5.5°C | 2.8°C | 26mm | 5 days | Dry and cold. Ice on sidewalks. |
📊 Temperatures: Open-Meteo ERA5 reanalysis (central Seoul, 2020–2025) 🌧️ Rainfall: Open-Meteo Archive, same period 📍 Use the calculator above for your specific dates.
So — What to Bring, What to Leave
After all those numbers, the packing logic is simple. Bring what the weather dictates (clothes). Rent everything bulky that the weather doesn’t care about.
Pack — season-specific essentials:
- Clothes for the season, with an emphasis on mid-layers you can stack and shed
- Shoes that can handle 15,000+ steps a day and won’t die in the rain
- Winter: thermal base layer, gloves, scarf (they take up almost no space)
- Summer: foldable umbrella and a thin cardigan — for the indoor AC, not the street
Leave at home — rent at Hongdae Station Exit 3 instead:
- Stroller ₩15,000/day~ — the most frequently damaged item in checked baggage
- Wheelchair / Rollator ₩15,000/day~ — bulky even folded, every airline has different rules
- Dyson hair tools ₩10,000/day~ — 220V/60Hz compatibility + cordless battery flight restrictions
- Travel cot ₩15,000/day~ — often cheaper than three nights of hotel crib fees
- Garment steamer ₩5,000/day~ — the difference between “suitcase-fresh” and actually fresh
From ₩5,000/day · Min. 2 nights 3 days · Hongdae Station Exit 3
KPLANZ is steps from Exit 3 of Hongdae Station (Line 2 / AREX Airport Railroad). You can step off the AREX from Incheon Airport, pick up your rentals without even going outside, and store your luggage at the same counter (from ₩30,000). Book at kplanz.com or DM us on Instagram.
Pack Less, Care More.
Frequently Asked Questions
What is the single most important packing rule for Seoul?
Layering. Seoul’s day-to-night temperature swing averages 11.4°C in March and 11.3°C in April. One outfit won’t get you from a 6°C morning to a 19°C afternoon. Bring a warm mid-layer and a shell you can remove — not one thick coat. In summer, the rule reverses: 29°C outside and 22°C inside, so always carry a thin cardigan for the air conditioning.
Which months are the hottest and coldest in Seoul?
Based on 2020–2025 measured data, the highest recorded temperature was 38.5°C (July) and the lowest was −18.8°C (January). July and August tie for warmest average high at 29.3°C. January is the coldest month: average high 2.4°C, average low −6.4°C.
When is Seoul’s rainy season and how much rain should I expect?
Late June through August. July averages 309 mm and August 332 mm, with about 19 rainy days each. But the year-to-year range is enormous — July alone has swung from 130 mm to 522 mm since 2020. Rain comes as short, intense downpours, not all-day drizzle. A compact umbrella and quick-drying shoes are far more useful than a rain jacket.
Do I need a winter coat in March or November?
March: yes, for the first half. The average low is 0.6°C and Seoul still logs about 14 sub-zero nights. November: yes, for the second half. The average low is 2.3°C with about 10 sub-zero nights. Both months live in the gap between seasons — winter mornings, spring (or fall) afternoons.
How cold does a Seoul winter really get?
Three-layer cold. Thermal base, knit, padded jacket — that’s the local standard. January averages −6.4°C low and 2.4°C high, with roughly 29 nights below freezing. The six-year record low is −18.8°C. Wind along the Han River and across open plazas makes the real-feel 5–8°C colder.
What should I rent in Seoul instead of packing?
Bulky or voltage-sensitive items. A stroller (₩15,000/day~), wheelchair or rollator (₩15,000/day~), Dyson hair tools (₩10,000/day~ — Korea uses 220V/60Hz, and plugging in your home-country device can be dangerous), travel cot (₩15,000/day~), or garment steamer (₩5,000/day~). KPLANZ is at Hongdae Station Exit 3, minimum rental 2 nights 3 days. Use your baggage space for season-appropriate clothes instead.