Any QB plays "better" in optimum weather conditions. Manning has both excelled and languished in inclement weather. I think the biggest question mark is how the O-line will come together and understand his cadence and protections. If they figure all of that out quickly and keep him upright, I don't care if they're in the middle of hurricane, Manning will make the correct reads and decisions.
Eric Decker and Demaryius Thomas are probably jumping for joy right now... they're going to be made famous and probably very rich.