Sling psychrometer. Dew point can be calculated using the air temperature and a relative humidity value, which is measured using something called a sling psychrometer. A psychrometer is a metal rod, around 6 inches long, that has a thermometer attached at the top.

What instrument measures dew point and relative humidity?

A hygrometer measures humidity. A sling psychrometer measures wet bulb and dry bulb from which you can get temperature, dewpoint and relative humidity. A radiosonde (or rawinsonde) is a package of weather instruments attached to a weather balloon that radios back to earth upper air observations.

What is a dewpoint thermometer?

Dew point thermometers are often used to exclude condensation as a cause of moisture damage in buildings. It is helpful that the dew point thermometer always measures the air temperature and humidity to determine the dew point temperature.