Here are a few examples from my eBay store, Atlanta Golf Shop, of winter items I have sold this summer. So you can see the proof is in the pudding. Some items have been listed a while, others were newly listed. Bottom line - if you list it, they will come!
I think you get the idea. This post isn't to brag but to show what is possible. eBay knows no seasons. If you find it, list it. If you have it, list it. If you aren't listing winter clothing in the summer you are leaving money on the table. And maybe a lot of money.
Learn more about selling thrifted clothing on eBay by taking my downloadable courses and learn what else you might be passing by that has value on eBay.