Why is hell thought to be hot, and not cold?

And say, "The truth is from your Lord, so whoever wills - let him believe; and whoever wills - let him disbelieve." Indeed, We have prepared for the wrongdoers a fire whose walls will surround them. And if they call for relief, they will be relieved with water like murky oil, which scalds [their] faces. Wretched is the drink, and evil is the resting place. (Holy Quran, 18:29).