| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 10° | — | 70.6mm | 10.2 | 48 |
| February | 10.8° | — | 81.8mm | 10.1 | 50 |
| March | 14.2° | — | 103.6mm | 10.8 | 60 |
| April | 18.6° | — | 131.1mm | 10.2 | 75 |
| May | 23° | — | 136.4mm | 9.5 | 81 |
| June | 26° | — | 234.9mm | 11.7 | 77 |
| July | 30° | — | 328.7mm | 12.8 | 62 |
| August | 31.5° | — | 211mm | 10.6 | 61 |
| September | 28° | — | 174.7mm | 10.3 | 75 |
| October | 23.2° | — | 92.6mm | 7 | 86 |
| November | 17.7° | — | 77.4mm | 9.1 | 74 |
| December | 12.5° | — | 72.4mm | 10.4 | 55 |
January in Shimonoseki averages a daily high of 10°C. Expect roughly 10.2 wet days totalling 70.6mm. Demanding conditions — pack for it and plan indoor options.
February in Shimonoseki averages a daily high of 10.8°C. Expect roughly 10.1 wet days totalling 81.8mm. Demanding conditions — pack for it and plan indoor options.
March in Shimonoseki averages a daily high of 14.2°C. Expect roughly 10.8 wet days totalling 103.6mm. Generally workable, with some weather to plan around.
April in Shimonoseki averages a daily high of 18.6°C. Expect roughly 10.2 wet days totalling 131.1mm. Comfortable conditions for being outdoors all day.
May in Shimonoseki averages a daily high of 23°C. Expect roughly 9.5 wet days totalling 136.4mm. Comfortable conditions for being outdoors all day.
June in Shimonoseki averages a daily high of 26°C. Expect roughly 11.7 wet days totalling 234.9mm. Comfortable conditions for being outdoors all day.
July in Shimonoseki averages a daily high of 30°C. Expect roughly 12.8 wet days totalling 328.7mm. Generally workable, with some weather to plan around.
August in Shimonoseki averages a daily high of 31.5°C. Expect roughly 10.6 wet days totalling 211mm. Generally workable, with some weather to plan around.
September in Shimonoseki averages a daily high of 28°C. Expect roughly 10.3 wet days totalling 174.7mm. Comfortable conditions for being outdoors all day.
October in Shimonoseki averages a daily high of 23.2°C. Expect roughly 7 wet days totalling 92.6mm. Comfortable conditions for being outdoors all day.
November in Shimonoseki averages a daily high of 17.7°C. Expect roughly 9.1 wet days totalling 77.4mm. Generally workable, with some weather to plan around.
December in Shimonoseki averages a daily high of 12.5°C. Expect roughly 10.4 wet days totalling 72.4mm. Generally workable, with some weather to plan around.
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. Shimonoseki peaks at 86.
Based on 30 years of records, May scores highest for comfort in Shimonoseki, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 31.5°C.
July is the wettest, averaging 328.7mm of rain across roughly 12.8 wet days.
January is the coolest month, with average daily highs around 10°C.