| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 2.1° | -5.4° | 14.2mm | 4.6 | 25 |
| February | 5.1° | -3.3° | 16mm | 3.2 | 38 |
| March | 10.1° | 1.7° | 50.6mm | 4.8 | 58 |
| April | 16.4° | 7.4° | 68.4mm | 5.8 | 77 |
| May | 21.8° | 12.3° | 112.4mm | 7.6 | 85 |
| June | 25.8° | 17.5° | 130.8mm | 8.8 | 82 |
| July | 27.9° | 21.3° | 357.6mm | 15.6 | 66 |
| August | 29.2° | 22.6° | 433.4mm | 10.8 | 70 |
| September | 26.1° | 17.4° | 131.9mm | 8.8 | 82 |
| October | 20.2° | 10.6° | 46.8mm | 5 | 90 |
| November | 12.1° | 3.5° | 50.4mm | 7 | 61 |
| December | 4.2° | -2.5° | 14mm | 3 | 37 |
January in Incheon averages a daily high of 2.1°C with nights around -5.4°C. Expect roughly 4.6 wet days totalling 14.2mm. A hard month to visit for comfort alone.
February in Incheon averages a daily high of 5.1°C with nights around -3.3°C. Expect roughly 3.2 wet days totalling 16mm. Demanding conditions — pack for it and plan indoor options.
March in Incheon averages a daily high of 10.1°C with nights around 1.7°C. Expect roughly 4.8 wet days totalling 50.6mm. Generally workable, with some weather to plan around.
April in Incheon averages a daily high of 16.4°C with nights around 7.4°C. Expect roughly 5.8 wet days totalling 68.4mm. Comfortable conditions for being outdoors all day.
May in Incheon averages a daily high of 21.8°C with nights around 12.3°C. Expect roughly 7.6 wet days totalling 112.4mm. Comfortable conditions for being outdoors all day.
June in Incheon averages a daily high of 25.8°C with nights around 17.5°C. Expect roughly 8.8 wet days totalling 130.8mm. Comfortable conditions for being outdoors all day.
July in Incheon averages a daily high of 27.9°C with nights around 21.3°C. Expect roughly 15.6 wet days totalling 357.6mm. Generally workable, with some weather to plan around.
August in Incheon averages a daily high of 29.2°C with nights around 22.6°C. Expect roughly 10.8 wet days totalling 433.4mm. Generally workable, with some weather to plan around.
September in Incheon averages a daily high of 26.1°C with nights around 17.4°C. Expect roughly 8.8 wet days totalling 131.9mm. Comfortable conditions for being outdoors all day.
October in Incheon averages a daily high of 20.2°C with nights around 10.6°C. Expect roughly 5 wet days totalling 46.8mm. Comfortable conditions for being outdoors all day.
November in Incheon averages a daily high of 12.1°C with nights around 3.5°C. Expect roughly 7 wet days totalling 50.4mm. Generally workable, with some weather to plan around.
December in Incheon averages a daily high of 4.2°C with nights around -2.5°C. Expect roughly 3 wet days totalling 14mm. Demanding conditions — pack for it and plan indoor options.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Incheon peaks at 90.
Based on 30 years of records, May–June scores highest for comfort in Incheon, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 29.2°C.
August is the wettest, averaging 433.4mm of rain across roughly 10.8 wet days.
January is the coolest month, with average daily highs around 2.1°C.