And it can't even be a lapsus where they meant Fahrenheit, because in that case it would be minus five Celsius, and in that case the water would have completely turned into ice.

Small things like that often kill one's suspension of disbelief much more than bigger, much weirder stuff: a guy who can fly/read minds/travel through time? I can get behind that. Getting wrong how the gravitational pull of the Moon works? Now that's ridiculous.