Autumn can be beautiful paddling weather, but water temperatures are dropping and hypothermia risk must be factored in. The American Canoe Association recommends the following: “if the water temperature is less than 60 degrees Fahrenheit and /or the combined air and water temperature is less than 120 degrees Fahrenheit, participants must wear wetsuits, dry suits or other appropriate clothing.”
Air + Water Temperature Formulas. There are a number of variations on this, but the gist of these formulas is that the combined air temperature Fahrenheit+ water temperature Fahrenheit must be above 120 or you need added protection from a wet or dry suit.
50-50-50 Rules There are a also number of variations on this rule, but it often goes something like this: “You have a 50-50 chance to swim 50 yards in water that is 50 degrees F without a wetsuit.”
Instead, the National Center for Cold Water Safety recommends the following:
They say that air temperature has nothing to do with cold water safety.
The only thing that matters when you’re in the water is the water temperature. The air temperature can be 80 or 90 degrees F, but if the water is 59 degrees F, you'd better be dressed for immersion in either a wetsuit or drysuit. So Always Dress For The Water Temperature Any water temperature under 70 degrees F requires caution. Many paddle organizations say water under 60 degrees F requires a wet or drysuit.
1. Always Wear Your PFD- A PFD greatly reduces the chance of sudden drowning due to cold shock and swimming failure. With few exceptions, cold shock occurs instantaneously and causes people to immediately lose control of their breathing in water as warm as 50-60F. As a result, many people can suddenly drown – even though they can swim and may even be near shore.
2. Field-Test Your Gear Most people who have thermal suits for paddling have never actually tried them out to see exactly what they do in cold water. Field testing shows you what your gear can and cannot do. (Note: Kate took this recommendation to heart and field-tested her farmer-john neoprene wetsuit on September 26. The air temp was 71F and the water temp was 58 F. Her exposed arms got cold fast, but otherwise she was very comfortable and could have stayed in the water a long time.)
3. Swim-Test Your Gear Every Time You Go Out Swim-testing catches mistake you may have made getting dressed—improperly zipped up gear, ripped seams you are unaware of. You can learn a lot from that regular swim tests, and that knowledge really sticks with you. If you're unwilling to swim-test, it may be because you're not confident that your gear will keep you warm and/or dry when you're in the water. You will develop a feel for cold water a lot faster if you make a habit of measuring the water temperature every time you swim-test. Measuring it yourself is better than hearing your buddy say "47 degrees" because you learn better by doing than by hearing.