Why do you think the author regularly points out that the dog seems to have a type of understanding of nature, and also that the man is oblivious to anything other than facts? What effect does that have on you as the reader?

Dogs work on instinct..... they naturally understand the threat of nature..... of the weather. The man did not seem to have any natural instincts, and like you say, he relied on facts..... things he'd read or learned, never understanding that nature doesn't act like a textbook. In my opinion, London accentuates the difference between the two in order that we understand the man's greatest mistake, a mistake that humanity has made over and over again throughout history..... thinking they can beat nature, hubris.