| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 10.2° | — | 50.5mm | 5.4 | 58 |
| February | 10.7° | — | 67.5mm | 7.5 | 55 |
| March | 14.2° | — | 109.7mm | 10.7 | 60 |
| April | 18.9° | — | 129.5mm | 11.6 | 73 |
| May | 23.5° | — | 135.8mm | 11.4 | 77 |
| June | 26.1° | — | 163.4mm | 12.3 | 75 |
| July | 29.9° | — | 136.8mm | 11 | 66 |
| August | 31.4° | — | 121.7mm | 9.7 | 63 |
| September | 27.7° | — | 210.4mm | 11.7 | 74 |
| October | 22.6° | — | 229mm | 11.4 | 77 |
| November | 17.6° | — | 101.5mm | 9.1 | 74 |
| December | 12.6° | — | 65.2mm | 6.5 | 63 |
January in Shiroi averages a daily high of 10.2°C. Expect roughly 5.4 wet days totalling 50.5mm. Generally workable, with some weather to plan around.
February in Shiroi averages a daily high of 10.7°C. Expect roughly 7.5 wet days totalling 67.5mm. Generally workable, with some weather to plan around.
March in Shiroi averages a daily high of 14.2°C. Expect roughly 10.7 wet days totalling 109.7mm. Generally workable, with some weather to plan around.
April in Shiroi averages a daily high of 18.9°C. Expect roughly 11.6 wet days totalling 129.5mm. Generally workable, with some weather to plan around.
May in Shiroi averages a daily high of 23.5°C. Expect roughly 11.4 wet days totalling 135.8mm. Comfortable conditions for being outdoors all day.
June in Shiroi averages a daily high of 26.1°C. Expect roughly 12.3 wet days totalling 163.4mm. Comfortable conditions for being outdoors all day.
July in Shiroi averages a daily high of 29.9°C. Expect roughly 11 wet days totalling 136.8mm. Generally workable, with some weather to plan around.
August in Shiroi averages a daily high of 31.4°C. Expect roughly 9.7 wet days totalling 121.7mm. Generally workable, with some weather to plan around.
September in Shiroi averages a daily high of 27.7°C. Expect roughly 11.7 wet days totalling 210.4mm. Generally workable, with some weather to plan around.
October in Shiroi averages a daily high of 22.6°C. Expect roughly 11.4 wet days totalling 229mm. Comfortable conditions for being outdoors all day.
November in Shiroi averages a daily high of 17.6°C. Expect roughly 9.1 wet days totalling 101.5mm. Generally workable, with some weather to plan around.
December in Shiroi averages a daily high of 12.6°C. Expect roughly 6.5 wet days totalling 65.2mm. 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. Shiroi peaks at 77.
Based on 30 years of records, April–June scores highest for comfort in Shiroi, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 31.4°C.
October is the wettest, averaging 229mm of rain across roughly 11.4 wet days.
January is the coolest month, with average daily highs around 10.2°C.