Temperatures are commonly measured in Fahrenheit in the United States, but Celsius is used in most other countries. Kelvins are the primary unit of measurement, which is a Celsius extension that goes all the way down to absolute zero. Absolute zero, or -273.15 ° C, is 0 kelvins. Water freezes at 32 ℉ (0 degrees Celsius) and boils at 212 ℉ (100 ° C).