Obviously massive spoilers for S06E01 & E02
This isn't on any book so far (we will see what happens when the sixth book comes out). On the show, we don't see a watch or calendar to know the exact times and dates, but I think we can deduce it as so:
It is night when Jon Snow is murdered (S05E10). On the next episode (S06e01), we see that there is some light coming in from the windows, so it must be the next day (~13.04)
Ser Allister gives Snow's friends until nightfall to surrender their arms (48.18):
At the end of the same episode, when Melissandre goes to sleep, it is still day outside (50.04):
So far my guess is that there have passed less that 24 hours.
On the second episode, the first scene we see with the Night's watch (wildling attack) is at night. This must be the night after the night of the murder, about 24h later (08.22):
And the final scene of the episode, where Melissandre ressurects Jon, is during the day most likely (light coming in from the windows). My guess is that it is the morning after the wildling attack (51.46):
So, to sum it up, I would say that between Snow's death and Resurrection, about 24-36 hours have passed.
Which would make sense:
- At night, Snow is murdered and his body is collected by friends
- The next morning, Ser Allister goes to the door of the room with the body and asks them to come out or he will kill them
- The same night Jon's friends refuse, get help from wildlings and Melissandre resurrects him the next morning.
Also, 24-36h is a reasonable amount. On the book, we learn about Lady Stoneheart, which died and several days passed before she was resurrected, and thus she couldn't talk because it was kind of too late. Snow seems okay (so far), but we'll see how well he is in the third episode.