| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -1.6° | -8.9° | 59.6mm | 12.8 | 4 |
| February | -0.6° | -9° | 38.4mm | 11.2 | 8 |
| March | 3.1° | -6.6° | 37.3mm | 9.3 | 14 |
| April | 7.4° | -2° | 39.1mm | 8.2 | 37 |
| May | 13° | 2.6° | 41.7mm | 9.9 | 58 |
| June | 18.3° | 8.2° | 55mm | 10.5 | 74 |
| July | 20.6° | 11.3° | 77.6mm | 12.2 | 76 |
| August | 20° | 10.4° | 93.4mm | 11.4 | 77 |
| September | 14.8° | 6.1° | 65.5mm | 11.8 | 60 |
| October | 8° | 1.5° | 81.9mm | 12.5 | 36 |
| November | 1.5° | -3.8° | 71.5mm | 13.5 | 9 |
| December | -1.1° | -7.9° | 63.4mm | 13.8 | 3 |
January in Sundsvall averages a daily high of -1.6°C with nights around -8.9°C. Expect roughly 12.8 wet days totalling 59.6mm. A hard month to visit for comfort alone.
February in Sundsvall averages a daily high of -0.6°C with nights around -9°C. Expect roughly 11.2 wet days totalling 38.4mm. A hard month to visit for comfort alone.
March in Sundsvall averages a daily high of 3.1°C with nights around -6.6°C. Expect roughly 9.3 wet days totalling 37.3mm. A hard month to visit for comfort alone.
April in Sundsvall averages a daily high of 7.4°C with nights around -2°C. Expect roughly 8.2 wet days totalling 39.1mm. Demanding conditions — pack for it and plan indoor options.
May in Sundsvall averages a daily high of 13°C with nights around 2.6°C. Expect roughly 9.9 wet days totalling 41.7mm. Generally workable, with some weather to plan around.
June in Sundsvall averages a daily high of 18.3°C with nights around 8.2°C. Expect roughly 10.5 wet days totalling 55mm. Generally workable, with some weather to plan around.
July in Sundsvall averages a daily high of 20.6°C with nights around 11.3°C. Expect roughly 12.2 wet days totalling 77.6mm. Comfortable conditions for being outdoors all day.
August in Sundsvall averages a daily high of 20°C with nights around 10.4°C. Expect roughly 11.4 wet days totalling 93.4mm. Comfortable conditions for being outdoors all day.
September in Sundsvall averages a daily high of 14.8°C with nights around 6.1°C. Expect roughly 11.8 wet days totalling 65.5mm. Generally workable, with some weather to plan around.
October in Sundsvall averages a daily high of 8°C with nights around 1.5°C. Expect roughly 12.5 wet days totalling 81.9mm. Demanding conditions — pack for it and plan indoor options.
November in Sundsvall averages a daily high of 1.5°C with nights around -3.8°C. Expect roughly 13.5 wet days totalling 71.5mm. A hard month to visit for comfort alone.
December in Sundsvall averages a daily high of -1.1°C with nights around -7.9°C. Expect roughly 13.8 wet days totalling 63.4mm. 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. Sundsvall peaks at 77.
Based on 30 years of records, June–August scores highest for comfort in Sundsvall, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 20.6°C.
August is the wettest, averaging 93.4mm of rain across roughly 11.4 wet days.
January is the coolest month, with average daily highs around -1.6°C.