Water boils at 100 degrees Celsius (212 degrees Fahrenheit) under standard atmospheric pressure, which is the pressure of sea level. This boiling point can change depending on the external pressure; for instance, at higher altitudes, the boiling point decreases due to lower atmospheric pressure. When water reaches its boiling point, it undergoes a phase change from liquid to gas, producing steam. This process is crucial in cooking, heating, and various scientific applications. Understanding boiling point variations plays a significant role in areas like meteorology, cooking, and engineering.