Wet Bulb Temperature Calculator — Stull Approximation | PsychroCalcLab

Determine thermodynamic wet bulb temperature. Essential for cooling tower sizing, evaporative cooling analysis, and human heat stress monitoring (WBGT).

How to Use

  1. Input the dry-bulb temperature and relative humidity.
  2. The results update automatically as you change the input values.
  3. Review the calculated value and the engineering notes shown below the result.

Frequently Asked Questions

Why is wet bulb lower than dry bulb?

Evaporation is a cooling process. As water evaporates from a wet wick, it removes heat, lowering the temperature unless the air is already at 100% humidity.

What is a dangerous wet bulb temperature?

A sustained wet bulb temperature of 35°C (95°F) is considered the limit of human survivability, as the body can no longer shed heat through sweating.

How does a cooling tower use wet bulb?

Cooling towers use evaporation to cool water. The theoretical limit of how cold the water can get is the ambient wet bulb temperature, not the dry bulb.