From what point of view is this story told?

Jack London's adventure story set in the Yukon is told from a third-person omniscient point of view. That means that the narrator knows the thoughts, actions, and feelings of all the characters; in the case of "To Build a Fire," the narrator's subjects are the unnamed man and the dog who accompanies him.
We know that the narrator knows the thoughts of the dog because the narrator says, "it knew this was no time for traveling."
Likewise, the narrator knows what is in the mind of the protagonist because even when the man does not speak, the narrator says, for example, "he was glad he was without a sled."
The omniscient narrator also knows things that the dog and the man do not know and communicates them to the reader, such as, "It was 75 below zero." London chooses this point of view of narration to develop characterization and plot in the only way possible since the dog cannot speak and the man dies at the end of the story (in the 1908 version).