I just went out on east grand traverse bay, ice on the shore... Blowing 15-25 knots, air temp 40, heavy rain sleet and snow to mostly cloudy, water temp 34(tops).. I wore a 4/3, with 5mm boots and hood, 3mm gloves, a 2mm core rash guard under my suit and I was sweating at times. I went for 2 hours and never felt a hint of chill until I sat on a bech for a couple beers while my kite dried out. Of course we are really lucky because the bay doesn't get much more then belly button deep for a long ways out and we can keep in the shallows.