I was born two years later so I don't remember that heatwave, or the Christmas snow, but I do remember my dad doing the snow tire ritual well into the 1970's. Back then, as well as the tire issue, was that nearly every car, except for the Olds Toronado, Cadillac Eldorado, and Buick Riviera were rear-wheel drive. And SUV's weren't a "thing" yet, so you at least needed snow tires to get around.