Hi Fireman,
Inverloch Windsurfing Club runs a Brass Monkeys Speed Challenge over the Winter months-
inverlochwindsurf.org.au/events/brass-monkeys-winter-speed-challenge/The challenge was to record the fastest speed on the coldest day
Generally , the coldest temps we recorded were around 12'C but wind chill would have brought it down to about 5'C....you certainly know you're alive when the mercury is in single figures!
On the flip side. its one of the pure joys of windsurfing....there's nothing better than a winter session..when the wind is biting, and the water gives you a permanent ice cream headache..you have the beach to yourself, and theres something awesome about knowing you are part of the 0.000001 of the population mad enough to venture out on the water at that time of the year...