Boiling point at altitude
The higher you are, the lower the temperature at which water boils. Enter an altitude to see the boiling point, or the reverse.
Nothing on our list is smaller: Denver is 1.01× higher. Water boils 5.304 °C cooler there than at sea level, so boiled food needs longer.
What it means
How high is that?
Standard atmosphere and the Antoine equation for water. Weather moves the real figure by about ±1 °C. Valid from 500 m below to 11 km above sea level.
Every unit
That altitude every way
Learn
Three things worth knowing
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1 °C every 300 m
Roughly 1 °C lower for every 300 m of height, or 1 °F lower for every 500 ft.
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A thermometer for altitude
Nineteenth-century explorers carried hypsometers, kettles with thermometers, and worked out their altitude from the temperature at which water boiled.
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Turning up the heat does not help
Boiling water cannot get hotter than its boiling point, however high the flame. Only a pressure cooker raises it.
Shortcuts
Popular altitude conversions
Background
About boiling at altitude
Water boils when its vapor pressure equals the pressure of the air around it. At sea level that is 100 °C (212 °F); higher up the air is thinner, so water boils sooner: about 1 °C lower for every 300 m, or 1 °F for every 500 ft.
Because boiling water is cooler, pasta, eggs and beans take longer at altitude, and recipes add time. On Everest water boils at about 70 °C, too cool to brew good tea.