cool, 
I had the most bizarre experience on the silk 850. Monday, felt super dialled, very happy. Wednesday, new spot, felt completely foreign, really struggling to link waves, stalling etc.
The difference, moving to a ~10°C colder spot. 22°C to 13°C. Spring-suit to 4/3mm.
The feeling was as if there was less lift, but also more drag! Turns felt fine, maybe smoother, but needed more power in the waves. Could partially put this down to the extra neoprene, but it felt radically different, as if I had put on a big, flat non-lifty but very draggy stab.
I had another session in glassy conditions at the colder spot, and even with the glassy clear water, the change was remarkable.
Now entirely convinced of the very negative impact of colder water (thread)