don't get me wrong...if everything comes together & the conditions are perfect (ie: little or no wind, sunny, warm air temp, minimal duckdiving), then a 4/3 is feasible in january or february. but how often does that happen? the best winter surf comes when it's windy & cold, by & large, & (at least here in nj) tends to involve a lot of duckdiving...something that gets pretty "exciting" in a sub-40° water in a 4/3. it's even more "exciting" in sub-35° water.
the guy is located in rhode island...those of you suggesting that a 4/3 is practical all winter up there are potentially endangering his life w/ crappy information.
It really depends on the deep ocean currents. New England gets a pretty good shot of the Labrador coming from the Arctic, but the severity depends on the greater climate like El-Nino/La-Nina. Notice how far up and close to the coast the Gulf Stream remained this summer, bringing warmer than usual water further North and mixing more North of Cape Cod. I think this could keep the water warmer for a longer time up there as long as the eddy keeps occurring in the same general area. However, RI can get some serious upwelling too--or at least that's what a buddy in Narragansett has told me.
Short answer--as long as you feel comfortable but I wouldn't push it too far. Not too many breaks in Rhodie you can get in and out of very easily and nearly impossible if someone has to drag you out.
Thanks guys if looks like I'll use my 4/3 with a hood boots and gloves till around Nov Dec then I'll have to sack up and buy a 6/5/4, appreciate everyone's suggestions.
Good till december w/ a 4/3.