| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -6.7° | -16.4° | 42.2mm | 16.5 | 0 |
| February | -5.8° | -16.6° | 34.7mm | 14.4 | 1 |
| March | 0.8° | -10.2° | 44.3mm | 14.6 | 1 |
| April | 7.7° | -3° | 71.7mm | 13.5 | 26 |
| May | 17.8° | 4.7° | 62.9mm | 13.5 | 66 |
| June | 22.8° | 10.1° | 69.9mm | 12.5 | 75 |
| July | 25.1° | 12.8° | 69.7mm | 12.4 | 75 |
| August | 23.5° | 12.3° | 78.2mm | 12.2 | 76 |
| September | 19.7° | 8.4° | 67.7mm | 12 | 75 |
| October | 11.5° | 2.4° | 87.2mm | 15.4 | 43 |
| November | 2.9° | -5.2° | 59mm | 15 | 4 |
| December | -3.6° | -11.3° | 49.9mm | 15.6 | 0 |
January in Greater Sudbury averages a daily high of -6.7°C with nights around -16.4°C. Expect roughly 16.5 wet days totalling 42.2mm. A hard month to visit for comfort alone.
February in Greater Sudbury averages a daily high of -5.8°C with nights around -16.6°C. Expect roughly 14.4 wet days totalling 34.7mm. A hard month to visit for comfort alone.
March in Greater Sudbury averages a daily high of 0.8°C with nights around -10.2°C. Expect roughly 14.6 wet days totalling 44.3mm. A hard month to visit for comfort alone.
April in Greater Sudbury averages a daily high of 7.7°C with nights around -3°C. Expect roughly 13.5 wet days totalling 71.7mm. A hard month to visit for comfort alone.
May in Greater Sudbury averages a daily high of 17.8°C with nights around 4.7°C. Expect roughly 13.5 wet days totalling 62.9mm. Generally workable, with some weather to plan around.
June in Greater Sudbury averages a daily high of 22.8°C with nights around 10.1°C. Expect roughly 12.5 wet days totalling 69.9mm. Comfortable conditions for being outdoors all day.
July in Greater Sudbury averages a daily high of 25.1°C with nights around 12.8°C. Expect roughly 12.4 wet days totalling 69.7mm. Comfortable conditions for being outdoors all day.
August in Greater Sudbury averages a daily high of 23.5°C with nights around 12.3°C. Expect roughly 12.2 wet days totalling 78.2mm. Comfortable conditions for being outdoors all day.
September in Greater Sudbury averages a daily high of 19.7°C with nights around 8.4°C. Expect roughly 12 wet days totalling 67.7mm. Comfortable conditions for being outdoors all day.
October in Greater Sudbury averages a daily high of 11.5°C with nights around 2.4°C. Expect roughly 15.4 wet days totalling 87.2mm. Demanding conditions — pack for it and plan indoor options.
November in Greater Sudbury averages a daily high of 2.9°C with nights around -5.2°C. Expect roughly 15 wet days totalling 59mm. A hard month to visit for comfort alone.
December in Greater Sudbury averages a daily high of -3.6°C with nights around -11.3°C. Expect roughly 15.6 wet days totalling 49.9mm. 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. Greater Sudbury peaks at 76.
Based on 30 years of records, June–September scores highest for comfort in Greater Sudbury, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 25.1°C.
October is the wettest, averaging 87.2mm of rain across roughly 15.4 wet days.
January is the coolest month, with average daily highs around -6.7°C.