What to wear to a trendy club saturday?!?

Ok i live in Texas and the weather just changed dramaticly the past week... so this saturday me and my fiance are going to this cool trendy bar/outdoor patio resturant. I want to look fab but its also like 45 degrees here at night .. so what should i wear? Half the place is of course inside and the other half is out. I need ideas pleeease! :) Thanks!