Chasing the aurora — The Northern Lights are why most people come, and the smart way to see them is to hand the problem to a guide. Aurora-chasing minibus tours pick you up in the centre after dark and drive — sometimes for hours, sometimes across the border into Finland — to wherever the sky is clearest that night, away from the city glow. Guides carry warm suits, hot drinks and cameras that pull the colour out of a faint band the eye reads as pale grey. The season runs roughly late September to late March, and the golden rule is simple: the lights need darkness, a clear sky and patience, so give yourself two or three nights rather than pinning everything on one.
Up the mountain on the Fjellheisen — Across the bridge on the mainland side, the Fjellheisen cable car climbs in a few minutes from Tromsdalen to a platform on Mount Storsteinen, around 421 metres up, for the definitive view over the island city, the bridges and the surrounding fjords and peaks. It is a prime spot in every season — the midnight sun wheeling low over the water in summer, the whole city glittering under snow in winter, and, on a clear dark night, the aurora overhead with the lights of Tromsø laid out below. There is a café at the top and marked trails on for the fit.
Out on the water for whales — In the cold months the fjords and coast north of Tromsø fill with orcas and humpbacks following the herring, and winter whale-watching boats run out to find them — the best sightings tend to be up the coast around Skjervøy, so the longer trips are the serious ones. It is properly Arctic: wrap up, watch black dorsal fins cut the grey water against snow mountains, and accept that wildlife keeps its own timetable. In summer the same quays send fjord cruises out under the midnight sun instead.
Dog-sledding, reindeer and Sami culture — Beyond the city the valleys hold husky and reindeer camps, and a half-day out is one of the great Arctic experiences — mushing a team of huskies across the snow, or riding a reindeer sled and sharing a fire and a meal with Sami herders who explain a culture built on following the reindeer. It is hands-on and memorable, and one of the few ways to feel the land the way the people who have always lived here do. Tours run from the centre with transport laid on.
The polar city itself — Between the big excursions, Tromsø rewards a slow wander. The Polar Museum, in an old customs warehouse on the water, tells the hard story of Arctic exploration and hunting that made the city's name. The wooden Tromsø Cathedral is a rare timber cathedral; the Arctic Cathedral across the bridge runs atmospheric midnight-sun and evening organ concerts under its soaring white roof. And the Mack brewery — one of the world's northernmost — pours its beer in the old Ølhallen hall, the right place to end a cold day.