No shirt season Share definition Flag If it's under 65 degrees, it's sweat shirt weather and shirts are prohibited/ not suggested "It's 63 degrees! Finally I don't have to wear a shirt." "I love No Shirt Season!" No shirt season by getyourshirttogether September 30, 2012 0 0 Get merch Get the No shirt season mug. Buy Now — $32.95 See more merch