| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -0.1° | -9° | 82mm | 12.5 | 5 |
| February | 0.7° | -8.2° | 75.9mm | 10.6 | 9 |
| March | 3.9° | -4° | 98.6mm | 12.6 | 14 |
| April | 8.7° | 0.7° | 92.1mm | 12.2 | 37 |
| May | 13.3° | 5.1° | 90.5mm | 12.2 | 54 |
| June | 17.5° | 9.2° | 108.6mm | 12.8 | 66 |
| July | 20° | 12.1° | 80.4mm | 11.7 | 77 |
| August | 20.9° | 12.6° | 79.3mm | 9.9 | 80 |
| September | 18.3° | 10.1° | 102.6mm | 9.3 | 76 |
| October | 13.4° | 5.7° | 119.3mm | 11.4 | 56 |
| November | 8.1° | 0.4° | 103mm | 11.2 | 37 |
| December | 3° | -5° | 109.2mm | 13.1 | 9 |
January in Saint John averages a daily high of -0.1°C with nights around -9°C. Expect roughly 12.5 wet days totalling 82mm. A hard month to visit for comfort alone.
February in Saint John averages a daily high of 0.7°C with nights around -8.2°C. Expect roughly 10.6 wet days totalling 75.9mm. A hard month to visit for comfort alone.
March in Saint John averages a daily high of 3.9°C with nights around -4°C. Expect roughly 12.6 wet days totalling 98.6mm. A hard month to visit for comfort alone.
April in Saint John averages a daily high of 8.7°C with nights around 0.7°C. Expect roughly 12.2 wet days totalling 92.1mm. Demanding conditions — pack for it and plan indoor options.
May in Saint John averages a daily high of 13.3°C with nights around 5.1°C. Expect roughly 12.2 wet days totalling 90.5mm. Demanding conditions — pack for it and plan indoor options.
June in Saint John averages a daily high of 17.5°C with nights around 9.2°C. Expect roughly 12.8 wet days totalling 108.6mm. Generally workable, with some weather to plan around.
July in Saint John averages a daily high of 20°C with nights around 12.1°C. Expect roughly 11.7 wet days totalling 80.4mm. Comfortable conditions for being outdoors all day.
August in Saint John averages a daily high of 20.9°C with nights around 12.6°C. Expect roughly 9.9 wet days totalling 79.3mm. Comfortable conditions for being outdoors all day.
September in Saint John averages a daily high of 18.3°C with nights around 10.1°C. Expect roughly 9.3 wet days totalling 102.6mm. Comfortable conditions for being outdoors all day.
October in Saint John averages a daily high of 13.4°C with nights around 5.7°C. Expect roughly 11.4 wet days totalling 119.3mm. Generally workable, with some weather to plan around.
November in Saint John averages a daily high of 8.1°C with nights around 0.4°C. Expect roughly 11.2 wet days totalling 103mm. Demanding conditions — pack for it and plan indoor options.
December in Saint John averages a daily high of 3°C with nights around -5°C. Expect roughly 13.1 wet days totalling 109.2mm. 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. Saint John peaks at 80.
Based on 30 years of records, July–September scores highest for comfort in Saint John, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 20.9°C.
October is the wettest, averaging 119.3mm of rain across roughly 11.4 wet days.
January is the coolest month, with average daily highs around -0.1°C.