| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 9.3° | — | 39.7mm | 4.7 | 56 |
| February | 9.9° | — | 56.6mm | 6.8 | 54 |
| March | 12.9° | — | 98.4mm | 9.8 | 58 |
| April | 17.9° | — | 126.5mm | 11.6 | 70 |
| May | 22.4° | — | 145mm | 12 | 76 |
| June | 25° | — | 150.5mm | 12.6 | 75 |
| July | 29° | — | 150.3mm | 13.3 | 65 |
| August | 30.3° | — | 131mm | 9.9 | 67 |
| September | 26.6° | — | 169.9mm | 11.9 | 76 |
| October | 21.4° | — | 201.7mm | 10.9 | 78 |
| November | 16.3° | — | 85.2mm | 8.8 | 71 |
| December | 11.5° | — | 52.1mm | 6.1 | 61 |
January in Ishioka averages a daily high of 9.3°C. Expect roughly 4.7 wet days totalling 39.7mm. Generally workable, with some weather to plan around.
February in Ishioka averages a daily high of 9.9°C. Expect roughly 6.8 wet days totalling 56.6mm. Demanding conditions — pack for it and plan indoor options.
March in Ishioka averages a daily high of 12.9°C. Expect roughly 9.8 wet days totalling 98.4mm. Generally workable, with some weather to plan around.
April in Ishioka averages a daily high of 17.9°C. Expect roughly 11.6 wet days totalling 126.5mm. Generally workable, with some weather to plan around.
May in Ishioka averages a daily high of 22.4°C. Expect roughly 12 wet days totalling 145mm. Comfortable conditions for being outdoors all day.
June in Ishioka averages a daily high of 25°C. Expect roughly 12.6 wet days totalling 150.5mm. Comfortable conditions for being outdoors all day.
July in Ishioka averages a daily high of 29°C. Expect roughly 13.3 wet days totalling 150.3mm. Generally workable, with some weather to plan around.
August in Ishioka averages a daily high of 30.3°C. Expect roughly 9.9 wet days totalling 131mm. Generally workable, with some weather to plan around.
September in Ishioka averages a daily high of 26.6°C. Expect roughly 11.9 wet days totalling 169.9mm. Comfortable conditions for being outdoors all day.
October in Ishioka averages a daily high of 21.4°C. Expect roughly 10.9 wet days totalling 201.7mm. Comfortable conditions for being outdoors all day.
November in Ishioka averages a daily high of 16.3°C. Expect roughly 8.8 wet days totalling 85.2mm. Generally workable, with some weather to plan around.
December in Ishioka averages a daily high of 11.5°C. Expect roughly 6.1 wet days totalling 52.1mm. 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. Ishioka peaks at 78.
Based on 30 years of records, April–June scores highest for comfort in Ishioka, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.3°C.
October is the wettest, averaging 201.7mm of rain across roughly 10.9 wet days.
January is the coolest month, with average daily highs around 9.3°C.