Dry Bulb Temperature is defined as what?

• A. The dew point temperature.
• B. The temperature felt by humans due to wind.
• C. Temperature of air measured by a thermometer freely exposed to the air, without accounting for humidity; the true thermodynamic temperature.
• D. The temperature adjusted for humidity.

Answer: (C)

Dry-bulb temperature is the actual air temperature as read by a standard thermometer exposed to the air, without accounting for humidity. It represents the true thermodynamic temperature of the air. In practice, the thermometer is placed in a radiation shield to minimize radiant heat from the sun, so the reading reflects the air’s temperature rather than radiant heat. This value is used with humidity data to determine other properties on psychrometric charts, such as relative humidity and dew point. It does not describe how hot or cold the air feels to people—that perception is influenced by humidity and wind and is captured by apparent-temperature indices. The other options describe humidity-related concepts (dew point, humidity-adjusted or perceived temperatures) rather than the actual air temperature read by the thermometer.