Depends on if you got a 3/2, 4/3,5/4, 3mm or higher,. If ya got a descent 3/2, I would say anything below 58 gets a little chilly. 4/3 really depends on what brand ya got. I have worn my latest 4/3 in 50 or a little below, beyond that good luck, thats when things get a bit hairy. I recommend you check out this company, they make some really good suits, go to the catalog, its worth it: http://www.westsurfing.com/
just got a lotus out of there, easily blows out any suit I have had.
I went out one day last year, in early November. The water was still warm, 68 degrees, but there was an offshore wind that was a bit chilly. I wasn't wearing a wetsuit and that wind kept blowing on the back of my neck, and after a while it felt like an ice cream headache, so after that I wore a wetsuit.
wb and you can find me at crystal and sweetwater and all over wb.
if your looking for a wetsuit go to wetsuitwarehouse.com they have all the best wetsuit manufactures and i use them for my wetsuit purchases also they give you a discount on some of them. but my advise is dont buy the gloves and booties from them buy them from a local surf shop.