Temperature is measured using different scales, and the main ones are Celsius, Fahrenheit, and Kelvin. These scales exist because people in different regions and fields developed their own systems based on convenience, history, and scientific needs. Understanding why they exist helps make sense of international temperature values.

Celsius is widely used around the world for everyday life. Its scale is simple, with freezing and boiling points of water as reference points. This makes it practical for weather, cooking, and general use, especially in countries outside the United States.

Fahrenheit is mainly used in the United States and a few Caribbean countries. It was developed with a different approach to make temperature changes more noticeable in daily life. Many Americans are familiar with Fahrenheit for weather forecasts, home heating, and other common measurements.

Kelvin was created for scientific purposes. Unlike Celsius or Fahrenheit, it starts at absolute zero, the point where all particle movement stops. Scientists and engineers use Kelvin because it provides an absolute, universal scale for experiments and technical work.

Different temperature scales exist because of historical, regional, and scientific reasons. While Celsius and Fahrenheit serve daily needs, Kelvin is designed for precision and science. Knowing why these scales exist helps people understand temperatures across different contexts and communicate clearly worldwide.