These are observational station locations, so typically located at airports, but will cluster in highly-developed countries and where people live or build thing

These are observational station locations, so typically located at airports, but will cluster in highly-developed countries and where people live or build things. Wet-bulb temperature is to first approximation the average of the dry-bulb (ambient temperature of air) and dew-point temperature (direct measure of amount of water vapour in air). So we're looking for places that can be both hot & wet in summer (e.g. eastern US) or really hot and still somewhat moist (e.g. near Arabian Sea) [0]. [0] https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classifica...