| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 0.2° | -6° | — | — | 27 |
| February | 0.9° | -5.8° | — | — | 27 |
| March | 4.9° | -1.7° | — | — | 40 |
| April | 10.5° | 3.4° | — | — | 64 |
| May | 16.8° | 9° | — | — | 84 |
| June | 22.6° | 15.2° | — | — | 94 |
| July | 25.6° | 18.3° | — | — | 94 |
| August | 25° | 18.2° | — | — | 94 |
| September | 21.5° | 14.7° | — | — | 94 |
| October | 14.9° | 8.4° | — | — | 78 |
| November | 8.5° | 2.7° | — | — | 57 |
| December | 3.1° | -2.3° | — | — | 33 |
January in Oakville averages a daily high of 0.2°C with nights around -6°C. A hard month to visit for comfort alone.
February in Oakville averages a daily high of 0.9°C with nights around -5.8°C. A hard month to visit for comfort alone.
March in Oakville averages a daily high of 4.9°C with nights around -1.7°C. Demanding conditions — pack for it and plan indoor options.
April in Oakville averages a daily high of 10.5°C with nights around 3.4°C. Generally workable, with some weather to plan around.
May in Oakville averages a daily high of 16.8°C with nights around 9°C. Comfortable conditions for being outdoors all day.
June in Oakville averages a daily high of 22.6°C with nights around 15.2°C. Comfortable conditions for being outdoors all day.
July in Oakville averages a daily high of 25.6°C with nights around 18.3°C. Comfortable conditions for being outdoors all day.
August in Oakville averages a daily high of 25°C with nights around 18.2°C. Comfortable conditions for being outdoors all day.
September in Oakville averages a daily high of 21.5°C with nights around 14.7°C. Comfortable conditions for being outdoors all day.
October in Oakville averages a daily high of 14.9°C with nights around 8.4°C. Comfortable conditions for being outdoors all day.
November in Oakville averages a daily high of 8.5°C with nights around 2.7°C. Generally workable, with some weather to plan around.
December in Oakville averages a daily high of 3.1°C with nights around -2.3°C. 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. Oakville peaks at 94.
Based on 30 years of records, June–September scores highest for comfort in Oakville, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 25.6°C.
January is the wettest, averaging —mm of rain across roughly — wet days.
January is the coolest month, with average daily highs around 0.2°C.