Costco Closed on Labor Day 2020 by Rhonda September 7, 2020 September 7, 2020 9/7/20. Costco will be closed on Monday, September 7, 2020, in observance of Labor Day. 0 FacebookTwitterPinterestEmail previous post Costco Sale – Life Comfort The Ultimate Throw next post Costco Sale: Gibson Sierra 6-Piece Bowl Set You may also like Mikasa Mango Wood Lantern Set at Costco! The Pad 17’x6′ by Aqua Lily Pad –... Kamado Joe Classic II Ceramic Charcoal Grill at... Cascade Mountain Tech Pool Noodle at Costco! Kwikset Halifax Lever Set – Costco Sale! Thomasville Abril 9-Piece Dining Set at Costco!