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Humidity

At 100% humidity the wet bulb temperature equals the air temperature. A sustained wet bulb temperature (where it's impossible to lose body heat through sweating and maintain body temperature) exceeding 35°C/95°F/308k may be fatal even to fit and healthy humans who are semi-nude, in the shade and next to a fan.

Pressure plays a part.

A typical domestic hygometer measures relative humidity. Capacitive is better than resistive.

Humans are more sensitive to variations in temperature than they are to changes in relative humidity.

Rewrite:

Humans are sensitive to humid air because the human body uses evaporative cooling as the primary mechanism to regulate temperature. Under humid conditions, the rate at which perspiration evaporates on the skin is lower than it would be under arid conditions. Because humans perceive the rate of heat transfer from the body rather than temperature itself, we feel warmer when the relative humidity is high than when it is low.

Typical relative humidity values are;

  • steam room: 100%

References

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Created: 2026-07-09

Last Updated: 2026-08-03