Actually, no I don't normally windsurf in the winter unless we get a warm stretch. It does happen sometimes. Right now I'm getting ready for a snowboarding trip. Been doing that for a long time too.
A big limiting factor is sensitivity to light due to the Photofrin. I have learned the hard way, a couple of times, what a severe burn you can get. A big help is the protective clothing I've gotten from Coolibar.com. This stuff really works. The material is cotton and bamboo fiber with zinc oxide woven into it. They claim 98% protection, and I think that's about right. But 98% is not good enough if you are going to be right out in the sun for significant periods. It does allow me to be out and about though.
I'm timing my outdoor sports for six or more weeks after the Photofrin treatments. Next PDT is in April, so that means late May through July will be good for outdoor stuff. Of course, the chemo and stent replacements put a damper on things at times. But hey, I'm happy to take what fun activities I can get!