Boiling temperature of water at different altitudes across the globe

Does water boil at different temperatures at different altitudes?? This question may seem pretty straightforward, but in reality it has many answers. It is due to the fact that that exact boiling temperature of water can vary from below 70 ˚C to over 101 ˚C. It is due to three main factors – atmospheric pressure, material of the vessel you are using and water purity.

How boiling works?

Boiling is the process of heating a liquid to a certain point where it rapidly evaporates. It happens when the vapour pressure of boiled liquid reaches the surrounding atmosphere. A basic school fact is that the boiling point of water is 100 ˚C, and this is true if you are boiling water at the sea level. There the vapour pressure equals the atmospheric pressure and that’s why you get this boiling temperature.

What is the water boiling point at different elevations?

At high altitudes there is a significant decrease of atmospheric pressure. This inevitably results in lowering the temperature at which water boils. The gas molecules in water stop being part of it more easily in lower atmospheric pressure conditions at high elevations.

For example if you manage to climb mount Everest and want to have a cup of tea, you’ll need to heat up your water to just below 70 ˚C. The maximum temperature at which water boils is measured at the Dead Sea. If you happen to boil water there, 101 °C is the heat you’ve to reach in order for water to boil.

The vessel is important factor

Many experiments has been made how water boils in vessels made from different materials. All of them show slight variations in boiling temperature. Water boiled in metal glasses boils faster, in glass is second and highest boiling temperature is measured for water in ceramic vessels. These temperatures vary with about 3 °C when measured at the same altitude.

Water purity affects boiling temperature

The third important factor that affects boiling temperature of water is its purity. Adding minerals such as common salt will increasing its boiling point. This is due to effect called boiling point elevation. This happens because of the more energy is required for water molecules to escape the boundary of its liquid form.

Water boiling temperature at different altitudes

PlaceElevationWater boiling temperature
Everest, NP8848m69.94 °C
Kilimanjaro, TZ5895m80.33 °C
La Paz, BO3640m87.71 °C
Albuquerque, US1619m94.6 °C
Denver, US1609m94.6 °C
Burj Khalifa, Dubai828m97.2 °C
CN Tower, Toronto553m98.2 °C
Willis Tower, Chicago442m98.5 °C
Empire State Building, New York381m98.7 °C
Minneapolis, US253m99.1 °C
Detroit, US200m99.3 °C
Birmingham, US196m99.3 °C
London, UK14m99.96 °C
Miami, US2m99.99 °C
Sea level0m100.0 °C
Baku, AZ-28m100.1 °C

Here are the boiling temperatures of water from 0 feet (0 m) to 15,000 feet (4572 m). The correlation between altitude and boiling temperature is clearly visible. Every 500ft (150m) increase of elevation decreases the boiling point by approximately 0.5 °C.

• 0 (0 m) – 212°F (100°C)
• 500 (150 m) – 211.1°F (99.5°C)
• 1,000 (305 m) – 210.2°F (99°C)
• 2,000 (610 m) – 208.4°F (98°C)
• 5,000 (1524 m) – 203°F (95°C)
• 6,000 (1829 m) – 201.1°F (94°C)
• 8,000 (2438 m) – 197.4°F (91.9°C)
• 10,000 (3048 m) – 193.6°F (89.8°C)
• 12,000 (3658 m) – 189.8°F (87.6°C)
• 14,000 (4267 m) – 185.9°F (85.5°C)
• 15,000 (4572 m) – 184.1°F (84.5°C)

Conclusion

As you can clearly see the water boiling point is not absolute. It vary a lot and is affected by many factors. I hope that this information answer the question “Does water’s boiling point change with altitude?” It can be useful if you are cooking in high altitudes.

References

1. Wikipedia – Boiling Point
2. Engineering ToolBox
3. Boiling