Having gone into the water three times last winter, I decided to get an automatic-inflate Personal Floatation Device because they're comfortable and I will will wear it while fishing, not just running the boat. I have seen discussions about the ability of auto PFD's to fully inflate in cold weather, so I pulled out the owner's manual on my new Mustang hydrostatic auto PFD to see what they had to say. There is a section on useage below freezing, warning the user that at temperatures below freezing the vest may not adequately inflate. This particular manufacturer/model suggests that the PFD should be worn partially inflated (with the oral inflation tube). Knowing this, I would strongly urge owners of any auto-inflate PFD to check their owner's handbook on this subject. It could save your life. On the subject of cold water, I would also suggest putting extra clothing - and even a towel - into your boat. If you go into the water and have nothing else, put on your rain suit. It will trap your body heat and keep the wind out long enough to get to safety. One last tip - that cell phone won't do you any good if it goes into the water with you. Put it into a sandwich size zip-loc. It is still easily accessible, and will keep the phone dry and ready for emergencies - even when you aren't! Be safe and Good Fishing!