WRT temperatures, same as others have commented, I remember not only talking cold weather in Centigrade and hot weather in Fahrenheit, but also remarking on it at the time - it made sense - zero °C is freezing and 100°F is very hot. Some time since then, I started to talk hot weather in Centigrade too, but I do not remember when or even recall the transition.
Fahrenheit now is difficult for me to put in perspective and I usually have to go to a converter. Particularly annoying when looking at sleeping bags/camping quilts aimed at the American market.