It sounds pretty good to me, unless the groom is going to be wearing shorts. Even then, you could always leave the jacket off, and roll up your sleeves. A linen suit would give the same option.
Do you know how formal the wedding is in general? Where is the couple from, and what did the invitation say/look like? And, if in doubt, ask the hostess what she thinks the gents will be wearing.
white pants AND shirt or no?
also, any idea what kind of shoes? i know it's not super formal.