| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 1.3° | -4° | 79mm | 17 | 6 |
| February | 1.9° | -3.6° | 67.2mm | 15.9 | 7 |
| March | 4.3° | -2° | 70mm | 17.3 | 14 |
| April | 8.8° | 1.3° | 50.6mm | 15.5 | 33 |
| May | 13.7° | 5.3° | 46mm | 16 | 50 |
| June | 17° | 8.9° | 70.6mm | 16.2 | 60 |
| July | 19.5° | 11.3° | 72.3mm | 17.1 | 68 |
| August | 18.5° | 10.8° | 86.6mm | 16.4 | 65 |
| September | 14.6° | 7.8° | 96.9mm | 17.2 | 53 |
| October | 8.9° | 3.1° | 81.5mm | 18.5 | 34 |
| November | 4.5° | -0.6° | 71.2mm | 14.6 | 17 |
| December | 2° | -3.4° | 84.6mm | 16.7 | 7 |
January in Trondheim averages a daily high of 1.3°C with nights around -4°C. Expect roughly 17 wet days totalling 79mm. A hard month to visit for comfort alone.
February in Trondheim averages a daily high of 1.9°C with nights around -3.6°C. Expect roughly 15.9 wet days totalling 67.2mm. A hard month to visit for comfort alone.
March in Trondheim averages a daily high of 4.3°C with nights around -2°C. Expect roughly 17.3 wet days totalling 70mm. A hard month to visit for comfort alone.
April in Trondheim averages a daily high of 8.8°C with nights around 1.3°C. Expect roughly 15.5 wet days totalling 50.6mm. A hard month to visit for comfort alone.
May in Trondheim averages a daily high of 13.7°C with nights around 5.3°C. Expect roughly 16 wet days totalling 46mm. Demanding conditions — pack for it and plan indoor options.
June in Trondheim averages a daily high of 17°C with nights around 8.9°C. Expect roughly 16.2 wet days totalling 70.6mm. Generally workable, with some weather to plan around.
July in Trondheim averages a daily high of 19.5°C with nights around 11.3°C. Expect roughly 17.1 wet days totalling 72.3mm. Generally workable, with some weather to plan around.
August in Trondheim averages a daily high of 18.5°C with nights around 10.8°C. Expect roughly 16.4 wet days totalling 86.6mm. Generally workable, with some weather to plan around.
September in Trondheim averages a daily high of 14.6°C with nights around 7.8°C. Expect roughly 17.2 wet days totalling 96.9mm. Demanding conditions — pack for it and plan indoor options.
October in Trondheim averages a daily high of 8.9°C with nights around 3.1°C. Expect roughly 18.5 wet days totalling 81.5mm. A hard month to visit for comfort alone.
November in Trondheim averages a daily high of 4.5°C with nights around -0.6°C. Expect roughly 14.6 wet days totalling 71.2mm. A hard month to visit for comfort alone.
December in Trondheim averages a daily high of 2°C with nights around -3.4°C. Expect roughly 16.7 wet days totalling 84.6mm. 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. Trondheim peaks at 68.
Based on 30 years of records, June–August scores highest for comfort in Trondheim, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 19.5°C.
September is the wettest, averaging 96.9mm of rain across roughly 17.2 wet days.
January is the coolest month, with average daily highs around 1.3°C.