Celsius works well for that. 0 is where water freezes. 100 is where water boils. 50 is the temperature where healthy people outside will die if they stay out

Celsius works well for that. 0 is where water freezes. 100 is where water boils. 50 is the temperature where healthy people outside will die if they stay out more than a hour or two. Humidity and altitude affect these numbers, but handy for reference.