| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 13.7° | 4.7° | 79.5mm | 11.5 | 57 |
| February | 16.3° | 6.6° | 63.4mm | 8.5 | 71 |
| March | 19.4° | 7.9° | 46.1mm | 7.6 | 83 |
| April | 22.5° | 9.5° | 20.5mm | 3.6 | 93 |
| May | 26.2° | 12.2° | 10.1mm | 2.4 | 95 |
| June | 30.6° | 14.8° | 2.1mm | 0.5 | 85 |
| July | 33.1° | 15.5° | 0mm | 0 | 76 |
| August | 32.1° | 15.4° | 0.4mm | 0.2 | 79 |
| September | 30.3° | 14.6° | 1.7mm | 0.4 | 86 |
| October | 25.1° | 11.9° | 9.1mm | 1.2 | 98 |
| November | 18.4° | 7.7° | 31.4mm | 4.7 | 85 |
| December | 13.6° | 4.7° | 74mm | 8.7 | 62 |
January in Brentwood averages a daily high of 13.7°C with nights around 4.7°C. Expect roughly 11.5 wet days totalling 79.5mm. Generally workable, with some weather to plan around.
February in Brentwood averages a daily high of 16.3°C with nights around 6.6°C. Expect roughly 8.5 wet days totalling 63.4mm. Generally workable, with some weather to plan around.
March in Brentwood averages a daily high of 19.4°C with nights around 7.9°C. Expect roughly 7.6 wet days totalling 46.1mm. Comfortable conditions for being outdoors all day.
April in Brentwood averages a daily high of 22.5°C with nights around 9.5°C. Expect roughly 3.6 wet days totalling 20.5mm. Comfortable conditions for being outdoors all day.
May in Brentwood averages a daily high of 26.2°C with nights around 12.2°C. Rain is rare — about 2.4 wet days and 10.1mm across the month. Comfortable conditions for being outdoors all day.
June in Brentwood averages a daily high of 30.6°C with nights around 14.8°C. Rain is rare — about 0.5 wet days and 2.1mm across the month. Comfortable conditions for being outdoors all day.
July in Brentwood averages a daily high of 33.1°C with nights around 15.5°C. Rain is rare — about 0 wet days and 0mm across the month. Comfortable conditions for being outdoors all day.
August in Brentwood averages a daily high of 32.1°C with nights around 15.4°C. Rain is rare — about 0.2 wet days and 0.4mm across the month. Comfortable conditions for being outdoors all day.
September in Brentwood averages a daily high of 30.3°C with nights around 14.6°C. Rain is rare — about 0.4 wet days and 1.7mm across the month. Comfortable conditions for being outdoors all day.
October in Brentwood averages a daily high of 25.1°C with nights around 11.9°C. Rain is rare — about 1.2 wet days and 9.1mm across the month. Comfortable conditions for being outdoors all day.
November in Brentwood averages a daily high of 18.4°C with nights around 7.7°C. Expect roughly 4.7 wet days totalling 31.4mm. Comfortable conditions for being outdoors all day.
December in Brentwood averages a daily high of 13.6°C with nights around 4.7°C. Expect roughly 8.7 wet days totalling 74mm. 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. Brentwood peaks at 98.
Based on 30 years of records, April–May scores highest for comfort in Brentwood, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 33.1°C.
January is the wettest, averaging 79.5mm of rain across roughly 11.5 wet days.
December is the coolest month, with average daily highs around 13.6°C.