Every kid in every shop in SD told me that all I would need in San Diego is a 3 mil when I moved out here 10 years ago... I tried a 3 mil suit the first winter out here. I stayed out every day all winter no matter the size or temperatures, and I would get cold all the time.... If there is heavy morning marine layer... if there are stiff winds. In the winter, I am usually out on deep reefs where you are dealing with more open ocean types of conditions while you are in the lineup... Winter surfing in San Diego is not like surfing the beach breaks in the summer. You are out very far, usually for a few hours... and when you wipe out on a big ass wave in cold deep water, the comfort of the 4 mil and not being cold helps you mentally. So the water gets down to 56 degrees, and for me, that is not 3 mil temps....

I tried. It just didnt work for me.....

I know there are 3 mils that are super warm and could work, but my 3.5 mil Pyscho Freak is perfect all year.