The Costco October 2026 shopping guide covers the most commercially eventful 40-day stretch in the Costco seasonal calendar — a sequence of overlapping promotional events, major new merchandise arrivals, and critical buying windows that rewards the member who understands the calendar and penalizes the member who shops randomly. From September 21 through October 31, Costco's commercial calendar delivers five distinct shopping events that the strategic member navigates as a coo

The October 2026 book covers September 21 through October 18 — 28 days of Member-Only Savings that span the transition from the September back-to-school and household reset period into the October commercial calendar that the October guide documents: the Halloween Treats Sale (October 22-31), the Holiday Savings Book arrival (approximately October 19), and the beginning of Costco's holiday commercial season. The October 2026 coupon book's commercial character is specific and