Americans use Fahrenheit, the rest of the world uses Celsius. This causes constant confusion! "Is 25 degrees hot or cold?" I hear this constantly from my American friends.
The Quick Reference
0°C = 32°F (freezing). 20°C = 68°F (room temp). 37°C = 98.6°F (body temp). 100°C = 212°F (boiling). These are good benchmarks!
For anything else, just use a converter. Way easier than trying to remember the formula!