In How I Contemplated The World From The Detroit House Of Correction And Began My Life Over Again, the narrator tells us that Simon's 'weather changes abruptly,' just like the weather in the city of Detroit. Here, weather symbolizes an emotional state, and Simon is certainly temperamental and mercurial due to his drug addictions. His mood changes as readily as the weather in Detroit.
He tells the narrator that he was once like Huckleberry Finn, but is now a Roderick Usher (Roderick is the protagonist in Edgar Allen Poe's The Fall Of The House Of Usher, whose fears and psychosis lead to his descent into insanity, and finally death). Indeed, Simon is plagued with 'frenzies and fears'; the narrator tells us that Simon is always cold. He imagines that the FBI will come for him and hound him over the Canadian border. Simon's unreliable temper renders him dangerous and unpredictable. The narrator tells us that she shivers when she thinks of Simon and that 'sixteen is not an age for shivering.'
The narrator is affected by Simon's hard-living and brutal treatment; he is abusive to her and prostitutes her without compunction. Like the weather in Detroit (which seems to be always 32 degrees), the narrator's life is fraught with uncertainty, danger from strange men, and the looming fear of possible death at Simon's hands. The pain of her degradation at sixteen causes her to 'shiver' and to fear for her future.