What September feels like in Trondheim
In Trondheim, September brings early autumn. Afternoons are cool, pleasant for walking as long as you keep a layer on. The gap between afternoon and night is small, so nights are cool and the temperature hardly changes after dark. Damp air makes the cold feel rawer than the numbers alone suggest.
Rain in Trondheim in September
September is persistently wet here: some rain falls on about every other day. Each rainy day adds about 7.8 mm (0.3 in), a proper wetting rather than a sprinkle. That is heavier than Trondheim's usual 6.2 mm per rainy day across the year. September is Trondheim's wettest month of the year.
Daylight and sunshine in September
In mid-September, sunrise is at about 6:39 am and sunset at about 7:48 pm (local time) — 13 h 9 min of daylight. Evenings are drawing in — 3 h 15 min less daylight than mid-August. About 57% of daylight hours are sunny; in short, sun and cloud share the day.
How September compares to the rest of the year
Ranked by average high, September comes out as the 4th warmest month in Trondheim. Compared with August, afternoons are 3.5°C (6.3°F) cooler, with 14 mm more rain. The cooling trend carries on into October. The next month's average high: 8.5°C (47.3°F).
Who September suits
- Sightseeing: less ideal — rain falls on more than half the days.
- Parks & outdoor: less ideal — too cool to sit outside for long.
- Beach: less ideal — the sea air is too cool.
- Museums & indoor: a good choice — with rain on most days, galleries and museums make easy plans.
Tips for visiting Trondheim in September
Rain Protection
Keep a small umbrella in your bag and wear shoes that cope with puddles.
Light Jacket
Bring a sweater or light coat for cool afternoons.
Sunglasses
Frequent sunshine — sunglasses and a light hat.
Quick questions
How warm is Trondheim in September?
Expect around 14.4°C (57.9°F) in the afternoon and 8.1°C (46.6°F) at night, which most visitors would call cool.
Does it rain a lot in Trondheim in September?
Quite a lot — 125 mm spread over about 16 days.
What should I wear in Trondheim in September?
Based on the averages: rain protection, a light jacket and sunglasses. Evenings feel similar to the day, so the same clothes work from morning to night.
Is September or October better for visiting Trondheim?
On our 12-month climate ranking, September comes out ahead (#5 of 12 vs #7). October is cooler and has more rainy days.