How to make my spring wedding dress work for fall?

Hi all, with all the lovely changes happening in the world lately, my fiancé and decided to postpone our June 6th wedding in Ohio to late October. Problem is, I bought a sleeveless wedding dress perfect for spring. My question is, how should I go about preparing to be warm in late October in the fall? Should I order an overcoat of some kind? Leggings? I'm not quite sure how to tackle this and I'm definitely not going to be shopping for a new wedding dress. Thanks in advance everyone, I'd love to hear any ideas.