| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 10.5° | — | 64.6mm | 9.8 | 50 |
| February | 12.1° | — | 92.3mm | 9.7 | 55 |
| March | 15.3° | — | 126.1mm | 11.4 | 62 |
| April | 19.8° | — | 157.8mm | 10 | 79 |
| May | 24° | — | 187.8mm | 10.3 | 79 |
| June | 26.6° | — | 332.9mm | 15 | 70 |
| July | 30.5° | — | 301mm | 13.3 | 59 |
| August | 32° | — | 236.1mm | 11.6 | 57 |
| September | 29° | — | 188.1mm | 10.5 | 71 |
| October | 24.2° | — | 122.6mm | 6.9 | 86 |
| November | 18.3° | — | 101.7mm | 8.7 | 77 |
| December | 13.2° | — | 78.7mm | 10.3 | 58 |
January in Isahaya averages a daily high of 10.5°C. Expect roughly 9.8 wet days totalling 64.6mm. Demanding conditions — pack for it and plan indoor options.
February in Isahaya averages a daily high of 12.1°C. Expect roughly 9.7 wet days totalling 92.3mm. Generally workable, with some weather to plan around.
March in Isahaya averages a daily high of 15.3°C. Expect roughly 11.4 wet days totalling 126.1mm. Generally workable, with some weather to plan around.
April in Isahaya averages a daily high of 19.8°C. Expect roughly 10 wet days totalling 157.8mm. Comfortable conditions for being outdoors all day.
May in Isahaya averages a daily high of 24°C. Expect roughly 10.3 wet days totalling 187.8mm. Comfortable conditions for being outdoors all day.
June in Isahaya averages a daily high of 26.6°C. Expect roughly 15 wet days totalling 332.9mm. Generally workable, with some weather to plan around.
July in Isahaya averages a daily high of 30.5°C. Expect roughly 13.3 wet days totalling 301mm. Generally workable, with some weather to plan around.
August in Isahaya averages a daily high of 32°C. Expect roughly 11.6 wet days totalling 236.1mm. Generally workable, with some weather to plan around.
September in Isahaya averages a daily high of 29°C. Expect roughly 10.5 wet days totalling 188.1mm. Generally workable, with some weather to plan around.
October in Isahaya averages a daily high of 24.2°C. Expect roughly 6.9 wet days totalling 122.6mm. Comfortable conditions for being outdoors all day.
November in Isahaya averages a daily high of 18.3°C. Expect roughly 8.7 wet days totalling 101.7mm. Comfortable conditions for being outdoors all day.
December in Isahaya averages a daily high of 13.2°C. Expect roughly 10.3 wet days totalling 78.7mm. 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. Isahaya peaks at 86.
Based on 30 years of records, April–May scores highest for comfort in Isahaya, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 32°C.
June is the wettest, averaging 332.9mm of rain across roughly 15 wet days.
January is the coolest month, with average daily highs around 10.5°C.