A paddling jacket is a good option but there are other alternatives.
I have a nylon/poly/spandex 3/4 zip top from REI which has kept me warm even after total submersion in a mountain stream with air temp in the upper 30's.

Magellan Neoprene Waders , I fell in a creek last year bank fishing water was freezing and I didnt even feel it, had to walk down the creek about 5 yards to where I could climb out plus they float so if I do fall out of my kayak they help me float and they are inexpensive .