The wet bulb temperature is a measure of air temperature that reflects the cooling effect of evaporation. It’s determined by taking the temperature of a thermometer with its bulb wrapped in a water-saturated cloth, which is then exposed to air. As water evaporates from the cloth, it cools the thermometer, and the resulting temperature reading is the wet bulb temperature.

This measurement is useful in several contexts:

1. Humidity Measurement: Wet bulb temperature, along with dry bulb temperature (the regular air temperature), can be used to calculate relative humidity and dew point. The greater the difference between the dry bulb and wet bulb temperatures, the lower the humidity.
2. Weather and Climate: It helps in understanding the cooling effect of evaporation in different weather conditions and can be used to assess heat stress on humans and animals.
3. Industrial Applications: In cooling systems and processes, wet bulb temperature is critical for designing and evaluating equipment that relies on evaporative cooling.

In essence, the wet bulb temperature gives an idea of how effectively evaporation can cool the air, which is particularly useful in understanding comfort levels and managing heat stress.