| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.8° | — | 167.8mm | 23 | 25 |
| February | 6.5° | — | 114.2mm | 18.5 | 27 |
| March | 10.2° | — | 102.8mm | 15.6 | 39 |
| April | 16.2° | — | 103.4mm | 13.7 | 60 |
| May | 21.9° | — | 101.2mm | 10.8 | 78 |
| June | 24.8° | — | 107.9mm | 10.5 | 79 |
| July | 28.9° | — | 250.1mm | 14.5 | 63 |
| August | 30.7° | — | 139.2mm | 10.4 | 64 |
| September | 26.6° | — | 154.1mm | 12.8 | 74 |
| October | 20.7° | — | 163.4mm | 14.9 | 70 |
| November | 14.6° | — | 192.5mm | 18.4 | 53 |
| December | 9° | — | 246.7mm | 23.6 | 35 |
January in Niitsu-honchō averages a daily high of 5.8°C. Expect roughly 23 wet days totalling 167.8mm. A hard month to visit for comfort alone.
February in Niitsu-honchō averages a daily high of 6.5°C. Expect roughly 18.5 wet days totalling 114.2mm. A hard month to visit for comfort alone.
March in Niitsu-honchō averages a daily high of 10.2°C. Expect roughly 15.6 wet days totalling 102.8mm. Demanding conditions — pack for it and plan indoor options.
April in Niitsu-honchō averages a daily high of 16.2°C. Expect roughly 13.7 wet days totalling 103.4mm. Generally workable, with some weather to plan around.
May in Niitsu-honchō averages a daily high of 21.9°C. Expect roughly 10.8 wet days totalling 101.2mm. Comfortable conditions for being outdoors all day.
June in Niitsu-honchō averages a daily high of 24.8°C. Expect roughly 10.5 wet days totalling 107.9mm. Comfortable conditions for being outdoors all day.
July in Niitsu-honchō averages a daily high of 28.9°C. Expect roughly 14.5 wet days totalling 250.1mm. Generally workable, with some weather to plan around.
August in Niitsu-honchō averages a daily high of 30.7°C. Expect roughly 10.4 wet days totalling 139.2mm. Generally workable, with some weather to plan around.
September in Niitsu-honchō averages a daily high of 26.6°C. Expect roughly 12.8 wet days totalling 154.1mm. Generally workable, with some weather to plan around.
October in Niitsu-honchō averages a daily high of 20.7°C. Expect roughly 14.9 wet days totalling 163.4mm. Generally workable, with some weather to plan around.
November in Niitsu-honchō averages a daily high of 14.6°C. Expect roughly 18.4 wet days totalling 192.5mm. Demanding conditions — pack for it and plan indoor options.
December in Niitsu-honchō averages a daily high of 9°C. Expect roughly 23.6 wet days totalling 246.7mm. 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. Niitsu-honchō peaks at 79.
Based on 30 years of records, May–June scores highest for comfort in Niitsu-honchō, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.7°C.
July is the wettest, averaging 250.1mm of rain across roughly 14.5 wet days.
January is the coolest month, with average daily highs around 5.8°C.