Joined: Jan 2009
Posts: 44,126
Likes: 6,342
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
I don't think the question makes much sense, because it depends on the layers themselves. If I wore thick layers, I would have fewer.
Today on my morning commute, I had four upper layers: a very thin wool t-shirt, a dress shirt, a cycling jacket/jersey kind of hybrid, plus a jacket.