When we went diving, we had to wear wetsuits because even in the summer, the Pacific Ocean here is very cold. Although the air was close to 70 degrees (Fahrenheit), the ocean was less than 60 degrees, which sounds similar but is actually very cold for water.
For reference, some marine animals like manatees cannot survive in water below 68 degrees. Think about all the fat a manatee has to help keep it warm, and then picture us in our (relatively) thin rubber wetsuits!
