Though the thought of slipping on a wooly layer while its blazing hot outside sounds unbearable, you can't deny how necessary a cardigan is to counteract that frigid air blowing out of the office vent. Sure, you might have a blanket draping over your chair when it's extra cold, but no one would take you seriously wearing that in a board meeting. The solution? These chic, office-appropriate knits that you can easily slip over your sleeveless dresses and tanks. In a flash, not only will you look stylish, but you'll be AC-ready, as well.