Since Halloween started trickling into stores in July, it shouldn't shock you that Christmas is in full swing at Costco — the aisles are filled with twinkling Christmas trees, ornaments, decorations, and gift-wrapping supplies. That observation from Best Life's shopping editors captures the specific commercial reality that experienced Costco members understand and first-time September holiday shoppers find surprising: the best time to shop for Christmas at Costco is not Decem