Celsius is a scale used to measure temperature, where water freezes at 0 degrees and boils at 100 degrees. It is commonly used around the world, especially in scientific contexts and in countries that have adopted the metric system. The scale is named after the Swedish astronomer Anders Celsius, who developed it in the 18th century. In everyday life, we often see temperatures reported in Celsius on weather forecasts and cooking recipes. For example, a pleasant day might be around 20 degrees Celsius, while a hot summer day could reach 30 degrees or more. Understanding Celsius helps us better relate to temperature changes in our environment.