Water boils at exactly 100°C (212°F) at normal atmospheric pressure. This is known as the boiling point of water, and it is the temperature at which water transitions from a liquid to a gas (steam) at normal atmospheric pressure. The boiling point of a substance is the temperature at which the vapor pressure of the liquid is equal to the atmospheric pressure, and for water, this occurs at 100°C. The boiling point of water can vary depending on factors such as the altitude and the atmospheric pressure, but at sea level and at normal atmospheric pressure, water boils at exactly 100°C.