Weather in Trondheim in January

The month to avoid. Of the twelve, January is the one to avoid. Highs sit at -0.2 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

January ranks 12 of 12 — near the bottom of Trondheim's year. July is the month that works, and the swing between the two is 54 points, which is a different holiday rather than a slightly better one.

Rain on 19 days, 4 of them heavy. Enough to need a plan B, not enough to need a plan around it. Layers, and a genuinely waterproof outer — at -0.2 °C the difference between a good day and a miserable one is entirely down to what you are wearing.

What the averages hide

Averages flatten a month, and this one hides a few things: 24 nights drop below freezing, so anything left outside stays frozen; the day barely swings — 4 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest January day reached 10.2 °C and the coldest night fell to -20.7 °C, and the wettest single day dropped 32 mm — roughly 25% of the month's rain in one day.

January is moderately variable: 10 mm in the driest year against 257 mm in the wettest, around an average of 129 mm. Roughly two Januarys in three land near that average, and the third does something else entirely.

Wind is light at 6.5 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 95%, which at -0.2 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How January sits in the year

Temperatures hold steady either side: 1 °C in December, -0.2 here, 0.2 in February. Nothing about the timing within the month matters much.

Daylight in January

5.6 hours of daylight, gaining 2.3 hours across the month. That is between Trondheim's extremes of 20.5 and 4.6 hours, so days are long enough not to constrain the plan.

Sea temperature

The sea sits at about 7.1 °C in January — too cold to swim without a wetsuit. The sea peaks at 14.2 °C in August and bottoms out at 6.1 °C — water lags the air by a month or two, which is why the best swimming often comes after the best weather.

How busy it gets

Off season. The genuine off season: cheapest by a distance, with the caveat that some tours and restaurants close entirely.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

January in Trondheim versus nearby

If Trondheim is one option among several, the nearby comparison is worth making. Oslo is close enough to be a coin toss — within a degree on temperature, 5 days less rain. Bergen is close enough to be a coin toss — within a degree on temperature, 3 days more rain.

So: January is a compromise. July is 54 points better and is what Trondheim is actually like at its best — worth moving the trip for if that is possible, and worth adjusting expectations for if it is not.

Every month in Trondheim

See all twelve months in Trondheim, or where else to go in January.