My Birthday's in the summer, but you think that would stop me from having a Halloween themed party? Hahaha. I'll probably wait until I move out and have it with friends and stuff though, since my grandma thinks Halloween is evil.
I would just get a bunch of halloween party favors marked down the day after halloween and save them for my birthday. I'll have to get fresh candy though, and I doubt I'll find any halloween themed candy, but having the decorations and the costumes and playing some spooky movies aughta do the trick.
It's never a wrong time of the year for spooks and scares (except maybe Christmas time...wait...sod that! That's what the Nightmare before Christmas is for!)