When the water evaporates, it triggers a process that causes cooling, just like sweating on the skin or on a drink that we wet trying to cool it.
The wet bulb temperature measures the lowest temperature that can be achieved with the evaporation process, which will then be lower than the normal temperature.
If the temperature of the wet bulb were to exceed 36 degrees for the human body there would be no escape, in fact in a few hours you would go into hypothermia.