It was like the reverse of winter sun. I’d swapped what had been a gorgeous slice of English summer for low single digits on a four-day cycle tour of the Norwegian island of Senja. Fortunately, the mercury “skyrocketed” by three degrees upon my arrival at Tromsø airport … ah, to be English and bringing the weather. I pulled on my long-johns, picked up my bike rental from Tromsø Outdoor and struck out for the coast.

If you know of Norway’s islands, it will probably be through the Lofoten archipelago: its pretty fishing hamlets and brooding massifs are beloved of tourism brochures and Hollywood was inspired by it – and created the animated movie Frozen, while a Matt Damon movie, Downsizing, will be released towards the end of the year. This summer it is expected to welcome more than 1 million visitors. Meanwhile, a short drive and a ferry hop north is quieter, glowering Senja.

Four times the size of the Isle of Wight, Norway’s second largest island (by area) resembles, on a map, a squashed cog. The Norwegian Scenic Route Senja that I followed – one of 18 national tourist routes that meander through the country – scours the spokes of the island’s north-west coastline for 63 miles, where the scenic drama of this “Norway in miniature’” crescendos. As the ferry from Brensholmen (an easy day’s ride from Tromsø) bore me and my 27-gear touring bicycle over the choppy jade sea to Senja, the island’s scale began to impose itself, the red clapboard houses like Monopoly pieces scattered on the craggy shores. In the interior, white mountains rose into cloud.

“Norway in miniature” is a description that gets thrown around a fair bit but if it’s anywhere, it’s Senja. There’s high drama in the west, with sheer, plunging fjords and a spine of jagged mountains (until the contours begin to space out in the south and east), through the forested interior and into the agricultural plain of the south-east. It’s quiet, too. The population is fewer than 8,000 and is spaced out among small villages centred around commercial fishing. The smell of drying fish in the wind is common; seeing another soul beyond the villages or away from the road isn’t.

I disembarked at Botnhamn and followed the road (route 862); the scenic way is marked with regular brown signs emblazoned with Viking knotwork. The road turned inland for a stretch past moorland. It was mid-summer but this far north the snowfields were only just beginning to reveal themselves as freshwater lakes. Snowmelt gurgled out of the brown grass. High overhead, cathedrals of black rock came into view.

Depending on fitness level, the route is easily divided into a two-day trip (or a more leisurely three-day trip of 20 miles each day). Two more days are required: at the beginning to follow the fjord out from Tromsø to Brensholmen (overnight at the four-star Sommarøy Hotel, doubles from £125 B&B, a short cycle from the port), and at the end to catch the scenic return ferry at Finnsnes. These are, perhaps, easy distances for a person of average fitness but I hadn’t reckoned on the last breaths of winter checking my descents and harrying my hill climbs. My quads burned for an e-bike.

Onto the west coast. A faint path in a layby led up to a circle of black ash burned in the mounded, cushion-soft vegetation, a viewpoint that snatched away my breath. This was Frozen for grown-ups.

“Would you like to go for a trail run?” said Radek, an employee of the only hotel in the Mefjordvær village (Mefjord Brygge, doubles from £92 B&B), as he stood outside my room that evening.

A generous invitation, though I opted for just a stroll through the charming village. The fjord was serene but I passed houses with their roofs bound to the earth with guy ropes. They knew what they were about – people at this location had weathered sea storms since the stone age. Future historians, however, if relying on the hotel’s brochures, will record that 21st-century Mefjordvær was a place where men caught and hugged halibut larger than themselves. Little surprise, then, when I found halibut served for tea. Simply fried in butter with a cream sauce, the meaty fish was so delicious I could have hugged it myself.

The clouds had lifted and the midnight sun, hovering just above the horizon, bathed the fjord’s rollercoaster topography in a burning orange light. At this latitude, from mid-May to mid-July, the sun never sets. In Tromsø’s Arctic Cathedral, midnight concerts are held daily during this period, the sleepless soothed by a programme of folk music, classical instrumentals, and, on my visit, a soaring rendition of Ave Maria.

With no cathedral handy, I took a constitutional up the nearby Knuten – a barren sea-facing hill where (according to a local guide) Senja’s last witch was burned in 1710. From the summit, the fields and birch wood surrounding Mefjordvær were flooded with a golden light. Climbing into bed at midnight, I lay awake beneath my eye mask. Perhaps a trail run here is the equivalent of a cup of chamomile?

At breakfast, I paused over the pickled herrings and made for the muesli. Back on the bike, and the first tunnel led me triumphantly into summer, the snow receded to gilt crowns on the fjord’s filed teeth, the harsh cries of terns replaced by the twitter of songbirds. Each turn of the squashed cog this day brought fresh scenic drama, my route skimming past inky seas where, between November and February, orcas and sea eagles vie for the herring.

Architectural curios are installed en route. Overlooking the majestic Bergsfjorden, for example, is a viewing platform-cum-art installation that projects into the air, or there’s the jagged wooden walkway at Tungeneset, complimenting the spiky surrounds. Less successful is the golden public loo of Ersfjorden that cost around £300,000 to overdesign. It’s shown up by the exquisite simplicity of the white-sand beach opposite, the water looking deceptively tropical close to shore.

After Bergsfjorden – and a detour to Skaland village for a waffle topped with Norway’s unusual savoury/sweet brown cheese – another seasonal switch. I emerged sweating from a tunnel into a winter wonderland, the white snow as thick and lush (and unwanted) as the tub of Norwegian fish gelato I would encounter on the boat back to Tromsø. I donned my coat and gloves, before hurtling down the mountain, eventually to arrive at the over-water village of Hamn i Senja. Skerries, ringed by azure shallows, breached the calm waters of the fjord. I rested with a glass of locally-brewed Senja IPA on the pier-side, and reflected on how the midnight sun could stretch out a truly lovely evening.

• Flights and accommodation were provided by Visit Norway with return flights from Heathrow with Scandinavian airlines