48 to 30s F (i.e. sub-10C) and wetsuit?
No effing way, thankyouverymuch.
If you like your cojones stuck way up there, with no chance of them descending into sight before New Year's Eve, knock yourself out and by all means dive wet. Me, I don't think that 's a very attractive prospect, so I'll continue to recommend a drysuit to anyone diving sub-10C (sub-50F) water.
BTW, my club arranged their annual Xmas tree dive last weekend. I wore a drysuit, drygloves and a Waterproof 10/5mm hood. Under the DS I wore a nice, warm undersuit, a wool wicking layer, one long and one short sleeve wool T-shirt, and two pairs of wool socks (one pair the thickness of tennis socks, one thick pair). I changed at home and showed up at the site wearing the wool and my undersuit, like I usually do for local dives. I was toasty warm all the time. Granted, it was mild: 6C air, 7C water. Quite balmy, in fact. But I still wouldn't have done that dive wet.