The boiling point of a substance is the temperature at which the substance boils, or enters a state of rapid evaporation. For pure water this is 100° Celsius or 212° Fahrenheit. This is measured at one atmosphere, that is, the air pressure at sea level.
The boiling point of a liquid depends on the pressure of the surrounding air. An increase in air pressure increases the boiling point; a decrease decreases the boiling point. In the low pressure environment at the top of Mt Everest for example, water boils at only 69 °C. (156.2 °F). It can also be defined in terms of vapour pressure as the temperature at which vapour pressure of liquid becomes equal to atmospheric pressure
Although when you add other substances to the water, you may need to add a large amount to see immediate changes in the boiling point.