| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 8.2° | 1° | 135.7mm | 19.5 | 31 |
| February | 10° | 0.9° | 90.6mm | 16.1 | 36 |
| March | 12.7° | 2.3° | 92mm | 18.2 | 47 |
| April | 15.9° | 3.9° | 62.6mm | 15.8 | 57 |
| May | 20.1° | 7° | 46.8mm | 11.7 | 77 |
| June | 23.3° | 9.5° | 30.8mm | 8.5 | 83 |
| July | 28° | 11.4° | 6.2mm | 2.7 | 91 |
| August | 28.2° | 11.4° | 11.4mm | 3.2 | 89 |
| September | 24.5° | 8.8° | 34.2mm | 7.4 | 85 |
| October | 17.6° | 5.4° | 78.9mm | 14.4 | 64 |
| November | 11.2° | 2.6° | 132.9mm | 19.1 | 42 |
| December | 7.7° | 0.8° | 156mm | 20.1 | 29 |
January in Hillsboro averages a daily high of 8.2°C with nights around 1°C. Expect roughly 19.5 wet days totalling 135.7mm. A hard month to visit for comfort alone.
February in Hillsboro averages a daily high of 10°C with nights around 0.9°C. Expect roughly 16.1 wet days totalling 90.6mm. Demanding conditions — pack for it and plan indoor options.
March in Hillsboro averages a daily high of 12.7°C with nights around 2.3°C. Expect roughly 18.2 wet days totalling 92mm. Demanding conditions — pack for it and plan indoor options.
April in Hillsboro averages a daily high of 15.9°C with nights around 3.9°C. Expect roughly 15.8 wet days totalling 62.6mm. Generally workable, with some weather to plan around.
May in Hillsboro averages a daily high of 20.1°C with nights around 7°C. Expect roughly 11.7 wet days totalling 46.8mm. Comfortable conditions for being outdoors all day.
June in Hillsboro averages a daily high of 23.3°C with nights around 9.5°C. Expect roughly 8.5 wet days totalling 30.8mm. Comfortable conditions for being outdoors all day.
July in Hillsboro averages a daily high of 28°C with nights around 11.4°C. Rain is rare — about 2.7 wet days and 6.2mm across the month. Comfortable conditions for being outdoors all day.
August in Hillsboro averages a daily high of 28.2°C with nights around 11.4°C. Expect roughly 3.2 wet days totalling 11.4mm. Comfortable conditions for being outdoors all day.
September in Hillsboro averages a daily high of 24.5°C with nights around 8.8°C. Expect roughly 7.4 wet days totalling 34.2mm. Comfortable conditions for being outdoors all day.
October in Hillsboro averages a daily high of 17.6°C with nights around 5.4°C. Expect roughly 14.4 wet days totalling 78.9mm. Generally workable, with some weather to plan around.
November in Hillsboro averages a daily high of 11.2°C with nights around 2.6°C. Expect roughly 19.1 wet days totalling 132.9mm. Demanding conditions — pack for it and plan indoor options.
December in Hillsboro averages a daily high of 7.7°C with nights around 0.8°C. Expect roughly 20.1 wet days totalling 156mm. A hard month to visit for comfort alone.
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. Hillsboro peaks at 91.
Based on 30 years of records, June–September scores highest for comfort in Hillsboro, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 28.2°C.
December is the wettest, averaging 156mm of rain across roughly 20.1 wet days.
December is the coolest month, with average daily highs around 7.7°C.