Timo, I get asked that all of the time, and to try and reduce how much I had to answer the question, wrote an article on some of the clothes I wear here:http://yakabout.com.au/home/content/view/420/101/
It was about 18 degrees celsius, and windy. I have yak fishied in zero degree temps in similar clothes before.
Thats a Hobie drytop by the way but I think the thick yellow ones have been replaced by the thinner red ones. I've tried both and prefer the older yellow one, by a large margin. It is warmer and keeps water out much better. I get asked about the pants alot to. They are Mountain Hardware stretchy wind-stopper pants, which were bought for hiking and motorbiking originally, but serve just as well as an outer layer for yak fishing.
Chris... Yakassa... I laughed out loud at that one. No Jap in my Pirate, but I am now wondering if RAM have a mount for a harpoon gun!