At the top of Mount Wellington, rising 1270-metres behind Hobart, sleet is lashing my cheeks and my stupidly bare knees as 12 mountain bikers and our Kiwi guide Matt prepare for our descent.

As Amos, the support-vehicle driver rather than the 750BC prophet, doles out gloves, high-vis vests and extra layers, some fellow riders indulge in mirth-filled "Facetime" that goes something like this

Them, chortling noisily: "We're on top of Mount Wellington and it's snowing."

Their friends: "We can't hear you and we don't know where you are but it looks like it's snowing."

Them:  "Yes, we're on top of Mount Wellington and ...

Meanwhile, two teenage Danes from Aarhus are strutting their stuff on their newly acquired velocipedes.

Facetime complete, we are under way, the rushing gale created by our motion spearing upwardly-mobile snow against my frigid limbs.  Why  did I think cycling shorts  were a good idea, I ask myself, as I lose the feeling in my knees and, oddly, my inner thighs?

"From here, you'd normally be able to see right across Hobart, over all the bays around and down to Bruny Island," says  Kiwi Matt at our first stop inside a swirl of icy mist.

"Trust me, it's a wonderful view," he adds.

With the next four-kilometre downhill section finally taking us out of the cumulus, I have to restrain myself from overtaking our guide, narrowly avoiding a wipeout on the notorious Shoe-bridge bend where many first-timers come a cropper.

The two lanky Danes speed past me, performing "bunny-hops" and "kick-outs".

Approaching our second stop, Kiwi Matt, not possessing brake lights, holds up a gloved hand.  Danish Stig either doesn't see him and jams on the brakes or attempts a wheel-screeching slide.

Either way, his bike disappears from beneath him, planting him firmly on his Aarhus.

Further down the meaty tor, which is to Hobart as the Blue Mountains are to Sydney only smaller and closer, the 10 most daring riders take a steep off-road track.

"Now be careful," cautions Kiwi Matt, "this vertical's a bit gonzo".

Plummeting down the stony trail, mud slaps my thighs with equal velocity as the earlier snow and every bump threatens to jettison me into the Tassie bush to "collect a Christmas tree", as a stack in woods is known among mountain bikers.

But in five minutes, coated head to toe in sludge, like an escapee from a Mount Wellington spa, I emerge at the trail end, slightly ahead of a grimacing Stig.

Back on the curling road in the foothills it's a balmy 15 degrees and I'm beginning to anticipate dinner at the Latin American-themed Frank, Hobart's hot new harbourside restaurant.

My legs are thawing, I can feel my inner thighs again and I'm even feeling bonhomie for my Facetiming mates.

We make a final stop outside Cascade brewery and continue down through Hobart's suburbs to the Salamanca waterfront, where Stig's mate, Sven,  attempts an improbable "pogo" off the pavement, which leaves the acro-brat nursing his testicles.

It's the delightful denouement to my summit-to-sea Hobart adventure, and a phenomenon I never thought I'd experience, a day when it snowed in Australia at Christmas.

Daniel Scott was a guest of underdownunder.com.au