For a population so adeptly conditioned to cold weather, Finns are surprisingly good at taking the heat.
Tossing a large ladle of water over hot coals, a glistening, tattooed Nordic grins gleefully as our dark, charcoal-stained smoke sauna transforms into an angry furnace.
As steam singes my nostrils and beads of sweat form rivulets in every fleshy fold, I bolt for the door and wonder if Brit basting is all part of the entertainment.
There are 3.3 million saunas in Finland, more than one for every other person, but the majority are private. Helsinki's new Loyly (a term used to describe the steam that rises when you throw water on the sauna's rocks) represents a return to public, social spaces.
The wooden, steep sloped structure, with a seaside bar terrace and open-air rooftop lounge, is also part of the Helsinki's drive to embrace outdoor spaces and bask in the long, warm days of short but sweet summers.
Elsewhere, a car park has been transformed into a pool complex and a new law has been passed allowing businesses to turn parking spaces outside buildings into temporary summer terraces. Subsequently, an apparently quiet capital is now outwardly effervescing with life.
Thankfully, I prevent my own blood bubbling so vigorously by retreating to Loyly's second, more sedate sauna, where horizontal pine slats act like Venetian blinds, revealing near naked bodies descending a step ladder into the sea.
Closer to town, next to the port and fried fish stalls of Market Square, the Helsinki Allas Pool is due to fully open later this month.
Locals and tourists are already making use of the dockside terrace, where filtered salt and fresh water swimming pools will be suspended in the harbour next to segregated saunas. The idea for the complex, previously a tarmac car park, was first touted 10 years ago and has been partly financed by crowdfunding.
Although paddling in the shadow of cruise liners is off-putting, the central location will no doubt prove popular, and owners plan to have a reserve of rentable swimwear for spontaneous sauna goers.
Along with cruise ships, sightseeing ferries servicing Helsinki's archipelago also leave from the port. Newly opened to the public this year is Vallisaari island, a 20-minute journey away.
Once occupied by Russia and later used as a military base, it's now a nature refuge. I follow gently rising trails to lookout points and watch sailing boats weave through islands, etching spirals on a duck egg blue watery canvas.
Strict regulations govern Vallisaari, which is off limits from 10pm to 6am, although there is talk of opening a Tentsile hotel on the island next year.
The gravity defying, British-made Tentsile Tree Tents, which appear to levitate above ground and are suspended between three trees, have developed a cult following in Finland, and adventure tour companies use them in nearby Nuuksio National Park.
Dominated by forest-covered valleys and deep rocky gorges, the park, which is a 45-minute drive from Helsinki, is busy with campers on a hot weekend in July.
According to the traditional Finnish legal concept of Everyman's Right, general public have the right to roam freely through wilderness areas. Only campfire sites are restricted, although stores of free firewood make them appealingly convenient to use.
We hike alongside sparkling, tree-lined lakes filled with lilies, clambering over moss-covered granite boulders in the dark forest canopy, as shards of light skip across glistening red toadstools.
"The elves have been playing here," laughs my guide Miki from Arctos Adventures, pointing to the disorderly mass of strewn stones.
Using thick pads to protect the trees, Miki sets up our tents next to the bathwater-warm Lake Kolmoislampi, while I wander off in search of blueberries.
"It's very Finnish to explore the forest alone and have an internal dialogue," explains Miki, and I enjoy every meditative minute of picking plump berries and staining my fingers purple in the process.
By midnight, it's still not completely dark. This is, after all, a Scandi summer.
Above me, wisps of treetops form charcoal scribbles in the sky, and in the distance I hear skinny dippers squeal as they splash in the lake.
Climbing into the Tentsile requires a big heave and a belly flop, but once inside, it's like sleeping in a spacious, supportive hammock. Air coolly circulates around my body and there are no irritating pinecones digging into my back.
But it's not just the freedom of movement that lulls me to sleep. Out here, surrounded by trees and toadstools, anything is possible. By nurturing nature on their doorstep, Helsinki's city dwellers have struck upon a truly fine way to live.
* The writer travelled as a guest of the Finnish Tourist Board.
