These formulas advise you to add air temperature + water temperature to determine whether you should wear thermal protection. In other words, they mistakenly say that if the air temperature is high enough, you can safely paddle on cold water without the protection of a wetsuit or drysuit.
A Common Example
If the combined air and water temperatures are below 120 degrees
Fahrenheit, a wetsuit is a must and a drysuit is highly recommended.
Using this formula, a paddler could mistakenly conclude that if the air temperature was 72F (22C), no protection would be needed in 53F (12C) water – because the total is above 120. (72F + 53F = 125) That’s simply incorrect.
The Cold Facts
There is absolutely no scientific information to support these formulas. Someone just made them up.
- 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 90F (27C or 32C), but if the water is cold, you'd better be dressed for immersion in either a wetsuit or drysuit.