Which temperature should be determined first, wet-bulb or dry-bulb?

The process of measuring temperature involves both wet-bulb and dry-bulb readings, but understanding the significance of each can determine the order in which they are typically obtained. In meteorological practice, dry-bulb temperature is generally measured first because it establishes the ambient temperature of the air.

The dry-bulb reading serves as the baseline temperature, while the wet-bulb temperature is a reflection of moisture content and cooling effects due to evaporation. If you take the dry-bulb measurement first, you can then gauge how much the temperature will drop as moisture evaporates from the wet-bulb thermometer, giving you an indication of relative humidity and dew point when both readings are analyzed together.

In many practical applications, such as in aviation weather reporting, knowing the conditions of the ambient air (dry-bulb temperature) before taking into account the cooling effects of moisture (wet-bulb temperature) is essential. Therefore, the sequence, starting with the dry-bulb measurement, provides a structured approach to understanding the overall temperature and humidity profile of the surrounding environment.