The dry-bulb temperature (DBT) is the temperature of air measured by a thermometer freely exposed to the air, but shielded from radiation.[1] DBT is the temperature that is usually thought of as air temperature, and it is the true thermodynamic temperature. It is directly proportional to the mean kinetic energy of the air molecules. Temperature is usually measured in degrees Celsius (°C), kelvins (K), or degrees Fahrenheit (°F). If expressed in kelvins, then the symbol Ta, if expressed in Celsius or Fahrenheit, then the symbol is ta. When measuring dry-bulb temperature care should be taken to prevent the sensor from being subjected to radiation from neighbouring heat sources.
Unlike wet-bulb temperature, dry bulb temperature does not indicate the amount of moisture in the air. DBT is one of the main input for thermal comfort calculations. DBT is an important variable in psychrometrics, being the horizontal axis of a psychrometric chart.