Halley is the British base on the Weddel Sea, at about 75S, 25W.
Brings back some cracking memories, I was 3rd mate / 2nd mate on the RRS Bransfield on her deployment to British Antarctic bases in 1995/96. One of the best trips I've ever done during a 35 year career at sea. Surprisingly, I never encountered any unduly cold temperatures during our Antarctic explorations, however the ships are only utilized during the halcyon Southern summer months!!
Canada brings back some pretty grim memories though, British Steel Iron Ore carriers trading up the Gulf of St Lawrence in the depths of winter to such places as Port Cartier and Sept Isles. Absolutely bloody freezing, brass monkeys & all. Not the sort of place to contemplate cycling. Cold enough for me now in Northern Scotland although still managing around 10 miles/day commuting courtesy of the Schwalbe studded tyres!!