Comment by ndsipa_pomu

> Fans do you no good when the humidity is above a certain point.

That would be related to the wet-bulb temperature. If the wet-bulb temperature is more than about 30°C, then I'd consider the area to be uninhabitable. (A wet bulb temperature of 35°C is considered lethal).

Fans are surprisingly effective as most people are stationary and thus produce almost a bubble of high humidity around themselves. Fans disperse that localised high humidity and allow people to effectively reduce their temperature through sweating/evaporation.