Incheon weather in September
September is one of the best months to visit Incheon: highs of 24°C (76°F) and about 138 mm (5.4 in) of rain on average. Nights average 16°C (62°F) and cloud cover 57% (NASA POWER, 2001–2025 averages). The sea averages 28°C (82°F). It is the 3rd wettest month of the year and the 4th warmest. Compared with August, it is cooler and drier; October brings highs of 18°C (65°F) and 53 mm (2.1 in) of rain.
Figures are long-term averages for Incheon, the largest city in Incheon. See below for other places.
Is September a good time to visit Incheon?
best month Weather score 66/100.
Yes. September is one of the best months for weather in Incheon.
Does it rain a lot in Incheon in September?
Some rain is normal: about 138 mm (5.4 in) falls in an average September. It is the 3rd wettest month of the year.
How warm is Incheon in September?
Days average 24°C (76°F) and nights 16°C (62°F).
Incheon weather by month
| Month | High | Low | Rain | Cloud | Sea | Weather |
|---|---|---|---|---|---|---|
| January | 1°C (33°F) | -7°C (19°F) | 20 mm | 56% | 4°C (38°F) | least pleasant |
| February | 3°C (38°F) | -5°C (23°F) | 31 mm | 52% | 3°C (37°F) | least pleasant |
| March | 9°C (47°F) | -1°C (30°F) | 37 mm | 50% | 6°C (42°F) | fair |
| April | 15°C (59°F) | 5°C (40°F) | 72 mm | 53% | 12°C (53°F) | fair |
| May | 21°C (70°F) | 11°C (51°F) | 84 mm | 56% | 17°C (63°F) | best |
| June | 25°C (78°F) | 16°C (61°F) | 116 mm | 65% | 24°C (75°F) | best |
| July | 27°C (81°F) | 21°C (69°F) | 361 mm | 76% | 28°C (82°F) | least pleasant |
| August | 28°C (83°F) | 22°C (71°F) | 260 mm | 65% | 31°C (87°F) | least pleasant |
| September | 24°C (76°F) | 16°C (62°F) | 138 mm | 57% | 28°C (82°F) | best |
| October | 18°C (65°F) | 10°C (49°F) | 53 mm | 44% | 21°C (70°F) | best |
| November | 11°C (51°F) | 3°C (37°F) | 47 mm | 52% | 15°C (60°F) | fair |
| December | 3°C (37°F) | -5°C (24°F) | 22 mm | 55% | 8°C (47°F) | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis), sea temperature from Open-Meteo Marine. Page updated . How we rate months
Weather across Incheon in September
Weather can differ a lot within Incheon: coasts, hills and mountains each have their own climate.
| Place | High | Low | Rain | Weather |
|---|---|---|---|---|
| Incheon | 24°C (76°F) | 16°C (62°F) | 138 mm | best |
| Ganghwa-gun | 24°C (74°F) | 20°C (68°F) | 129 mm | best |