Hello Ryan & Connor,
Great question!
I (Allan) was wading in the water with a Weddell seal and took some underwater footage. Keep in mind, however, that I was wearing what's called a 'DRY' suit. Unlike a SCUBA diving neoprent 'wet' suit that lets water come in contact with your skin, this DRY suit is completely sealed with attached hood and boots to keep everything but your face mask area covered. I am wearing warm, dry clothes under the suit!
The average water temperature in the area around Antarctica is 33°Fahrenheit. Below that things turn to ice. A diver that is properly equipped may stay in the water 20 minutes or so (it really depends on the diver and their equipment.)
If a person falls in the water without a survival suit or proper dry suit, it could end their life in a matter of minutes! The natural human response to immersion in cold water is to gasp, sucking in freezing water and preventing air from coming in. Hypothermia, your body temperature dropping, sets in quickly as well.