Thin light materials like silk and nylon can be used on a warm fall day or you can up the fabric weight to cotton or even wool for the tail end of autumn when it's feeling more like winter. (colorandgrace.com)
If you fancy heading further afield and your budget can stretch a bit, Canada is a great option, although the best lights are at the very end of autumn and into winter so it will be colder. (thetravelmagazine.net)