Jon is Azor Ahai
Do you recall the Warrior of Light? That guy that Melisandre keeps rambling about? Her divination says that Azor Ahai will have the blood of the dragon and he will be brought back to life in smoke and salt.
Every time Melisandre has looked into the fires to find out more information about Azor, she just sees things that are connected with snow. Is this a Coincidence?
We know that Jon will fight the White Walkers and the red priestess has already referred to the King of the North as the “The Prince That Was Promised”.