I really don't have a fixed lower temperature limit...
...though I do tend to limit the windspeed. Anything over 20 knots sustained and you start getting spray and the dodger gets too salt encrusted to see well. Much depends on the specific boat.
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Below freezing lines can freeze. An up-coming Practical Sailor article will describe treatments that waterproof, freezeproof, reduce water weight gain, reduce squeaking, and reduce running friction. No, not fabric softener. Since I don't like icy decks, I mostly skip sub-freezing days.
You have to be a bit more careful around plastics. Dodger windows will break if rolled, as will sail windows (the ropes and polyester sails are fine. I don't know about laminate sails; I'm guessing there are multiple answers to that one.
Switching from sun glasses to ski googles helps a lot. Powerstretch balacavas too. Really keeps the face warm. Really, the clothes in the OP's post are all wrong. Big hood instead of balcava and fleece hat. Sunglasses instead of ski googles. Big bulky coat instead of a base layer of flease and a windproof flease soft shell. Jeans (only at the mall or round the house) instead of ski pants or wind-proof flease and an underlayer. Pictured is how you dress to run to the mall, not for a day of athletic activity. REI can fix you up.
Everyone should have a pair of Carhart coveralls. Last a lifetime, VERY warm.
A cabin heater helps, so you can take a break as needed.
A few more thoughts:
http://sail-delmarva.blogspot.com/2009/12/winter-sailing.html
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And I'm not "younger", I just own more clothes now. We have a deep cockpit and a large dodger that I find just right.