"Under a tent" (or air temperature) is more useful. It is going to telly you how hot will be objects that come into equilibrium with air which you can't tell fr

"Under a tent" (or air temperature) is more useful. It is going to telly you how hot will be objects that come into equilibrium with air which you can't tell from wet bulb temperature. You can derive wet bulb temperature from air temperature and humidity. Also measuring air temperature is easier and more practical as it is just enough to measure temperature of an object that comes into equilibrium with air.