Wedding This Weekend...Buy a New Suit?

[dicelumpY2005]

I am attending a wedding reception this week, but not the ceremony. Is wearing a suit a must? Last wedding I went to I was in, so I, of course, had a tuxedo and not an actual suit. I notice many people at the reception were just shirt/tie/slacks/dress shoes. Not to mention the fact that its starting to get disgustingly humid around here... Necessary to buy a new suit for this affair? Shirt/tie/etc...just fine? Thoughts?