Narrated Abu Huraira:
The Prophet (ﷺ) said, "In very hot weather delay the Zuhr prayer till it becomes (a bit) cooler because the severity of heat is from the raging of the Hell-fire. The Hell-fire of Hell complained to its Lord saying: O Lord! My parts are eating (destroying) one another. So Allah allowed it to take two breaths, one in the winter and the other in the summer. The breath in the summer is at the time when you feel the severest heat and the breath in the winter is at the time when you feel the severest cold."
Sahih al-Bukhari 536, 537
If the heat of summer is due to Hell, then why is it winter in the southern hemisphere? And vice versa?