Hypothermia, in Hawaiian waters?
Yes. See the 77-78.1F sea surface temperatures versus Human body temperatures. Note how the wind speeds contribute to wind chill when you are immersed in the sea and your haed is exposed to the winds.
HYPOTHERMIA IN HAWAII
This general information is provided to help you recognize the onset of Hypothermia. It is not intended to replace professional medical attention. Even in Hawaii’s ocean waters the threat of Hypothermia exists. Hypothermia is the condition in which the body loses heat faster than it is producing it.
http://dlnr.hawaii.gov/dobor/boating-in-hawaii/hypothermia-in-hawaii/