Weather in Trondheim in October

The month to avoid. Of the twelve, October is the one to avoid. Highs sit at 8.4 °C and the day is short; this is an indoors-with-excursions month, not an outdoors-all-day one.

October ranks 7 of 12 in Trondheim: past the worst of the year but short of July, which is the month to book if the dates are open.

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 8.4 °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: 4 nights fall below freezing; the day barely swings — 4.8 °C between the overnight low and the afternoon high. Across the twenty years measured, the hottest October day reached 21.3 °C and the coldest night fell to -11.7 °C, and the wettest single day dropped 40 mm — roughly 33% of the month's rain in one day.

October is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest October on record still delivered 189 mm against 56 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 123 mm average is a reasonable planning figure, not a promise.

Wind is light at 2.9 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 92%, which at 8.4 °C means damp rather than muggy — the kind of cold that gets into a coat and stays there.

How October sits in the year

The month is on the way down: 5.9 °C cooler than September, with November dropping another 5.3 °C. The first week and the last are not the same trip.

Daylight in October

10 hours of daylight, losing 3.1 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 10.8 °C in October — 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

Quiet. Few other visitors, cheaper rooms, and a real chance some seasonal operators are shut.

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

October in Trondheim versus nearby

If Trondheim is one option among several, the nearby comparison is worth making. Oslo is a better bet in October — within a degree on temperature, 4 days less rain. Bergen is close enough to be a coin toss — within a degree on temperature, 1 day more rain.

So: October is a compromise. July is 35 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 October.