Anyone who has read the “Harry Potter” books and/or have seen the films must notice the lack of safety in the wizarding world. From the forbidden forest and deadly creatures at Hogwarts to Quidditch, wizards and witches seem to care little about safety.
That includes going into the water in cold weather. A good example is in “The Goblet of Fire”, when the Tri-Wizard champions have to compete in the black lake and each save one individual. However, they do it in February, where the weather freezes.
Although the novel doesn’t specify the champions’ outfits (I’m pretty sure, according to what I remember), in the movie, they wore summer attire, while everyone else wore winter gear. Fleur wore just a bathing suit, while the boys had knee-length shorts and tank tops. How were they not cold?
You’d think they would have worn long-sleeved wet suits, or did something to get the champions warmer. Do charms that prevent hypothermia exist in the “Harry Potter” universe? If so, does the black lake at Hogwarts have them?
Even if the answer to both questions is yes, there couldn’t have been any in that pond Harry jumped into in “The Deathly Hallows”, after stripping himself. After he leaped into the water, he didn’t seem to suffer one bit.
Lots of people point out that if there is a potion to regrow bones, there should be a spell or something to fix Harry’s eyesight. That way, he wouldn’t need glasses. So, could magic keep magicians from freezing and experiencing hypothermia?