Liquid spray on wax doesn't have residue usually. And wax in the shade. Anytime is ok but I don't think wax spreads very well if you're outdoors in the wintertime in NY.
You can always try those sealant stuff. Works pretty well from what I've seen. THen ya don't have to wax for quite a while. I've tried CrystalGuard. Not as smooth feeling as wax but looks just as shiny.