A temperature scale is a system used to measure and quantify temperature. The most common scales are the Celsius, Fahrenheit, and Kelvin. Each scale has its own reference points, such as the freezing and boiling points of water, which help to standardize temperature measurements. The Celsius scale is based on the freezing point of water at 0 degrees and boiling at 100 degrees. The Fahrenheit scale, primarily used in the United States, sets the freezing point at 32 degrees and boiling at 212 degrees. The Kelvin scale is used in scientific contexts, starting at absolute zero, the theoretical lowest temperature possible.