jesse,
i think the boo backed bow would be fine. what is the belly made from? one tip is to keep the bow excercised. while your out there, and especially before you shoot, do multiple short draws (12-18") working up towards your draw length, this works the limbs. this is something i do evrytime i pick up my wood bows after not shootin them for a while, but it is especially important in the cold. i never draw a wood bow to full draw with letting know i'm about to do so.
however, i have never seen temperatures like what your talking about...and don't want to. i would have sat it out inside by the fire with a flask of port, gloves, beenie, and wingeing like a baby!