Verdict: Excellent month
Seoul Weather in September
September hits the sweet spot in Seoul — highs around 26°C (79°F), ideal for a full day on foot. Expect showers on roughly 11 days of the month — rarely trip-ruining, worth planning around. Overall, September is one of the best months of the year to be in Seoul.
Average high
26°C / 79°F
Average low
18°C / 64°F
Rain days
~11
Precipitation
199 mm
What to pack for Seoul in September
- Summer clothes, plus one light layer for air-con and evenings
- A packable rain shell or compact umbrella earns its space
- Comfortable walking shoes — every guide on this site assumes you'll use them
September against the rest of the year
Warmest in Seoul: Jul (29°C / 84°F) · Coolest: Jan (2°C / 36°F) · Wettest: Jul (~20 rain days)
2°
-7°
Jan
6°
-4°
Feb
12°
0°
Mar
18°
7°
Apr
22°
12°
May
27°
18°
Jun
29°
22°
Jul
29°
23°
Aug
26°
18°
Sep
18°
9°
Oct
12°
2°
Nov
3°
-6°
Dec
Daily highs / lows in °C · bars show rain days per month · ERA5 climate normals (2020–2024)