A Very Large Coat
It’s still fall, so your thin, non-rumply coat will stand up for a while, but at some point things will get very very cold, and you’ll want something embarrassingly large to protect you from the elements. You may only wear it for a few weeks of the year, but when winter really kicks in, it’s an essential. (At least, for everywhere outside of California.)
This anorak from Danish designer Henrik Vibskov should fit the bill quite nicely. It’s a slicker Euro version of the duffel coats we usually gush about, but if things get slushy, you may be glad to have the update.
And the zipper, for that matter.