Seoul

Here's the thing about Seoul that catches most first-timers off guard: it's a four-season city that doesn't mess around. January hits you with bitter cold (around −5°C / 23°F), while July turns into a sauna where the humidity makes 28°C (82°F) feel like 35°C (95°F). But there's a reason locals get genuinely excited about spring and autumn—these two windows are legitimately special. April and October are when Seoul shows off. April brings cherry blossoms, softer light for photography, and temperatures around 15–20°C (59–68°F) that let you actually walk around without sweating through your shirt. October? That's the underrated gem—clearer skies than spring, highs settling around 18–23°C (64–73°F), and the city's autumn foliage starting to pop without the spring crowds.

The personality of each month matters here. April feels like Seoul is waking up—cafes spill onto sidewalks, parks are packed but in a celebratory way, and you'll catch street festivals and temple celebrations tied to the lunar calendar. October is quieter and crisper. The air quality tends to be better (no spring dust), and the light has that golden-hour quality all afternoon. You'll see fewer tour groups than spring, which means better prices on accommodations and way shorter lines at Gyeongbokgung Palace. Rainfall is lower in October too—April can surprise you with sudden showers, whereas October typically stays dry.

Now, the months to absolutely avoid: July and August are when Seoul becomes genuinely uncomfortable. You're looking at highs around 29–31°C (84–88°F), but paired with 70–80% humidity and monsoon rains that can flood subway entrances. It's not just hot; it's sticky, oppressive heat. January is the other extreme—brutal cold, gray skies, and short daylight hours (around 9.6 hours) that make the city feel claustrophobic. December can work if you want holiday markets and fewer tourists, but post-Christmas through early February is genuinely grim.

Looking at 2026 specifically: Seoul's climate isn't shifting dramatically year to year, but the city has gotten measurably warmer over the past decade. April now trends slightly warmer than it did in the 2010s, which is honestly fine—it just means layers matter less. October remains stable and reliable. Annual rainfall sits around 1,236 mm, with most of it concentrated in summer months, so spring and autumn stay relatively dry. If you're planning around weather alone, April and October aren't just good—they're the only months where Seoul feels genuinely comfortable for extended walking and exploration.