Outdoor misters work by an evaporative cooling system that changes the water from liquid to gas state. The water is the force through nozzles to create a delicate and gentle mist. The water pressure is the key to getting a "foggy" effect rather than droplets of water. If misters use large nozzles and low water pressure, they will get everything wet and not create a desirable cooling-down outcome. But, if they use high pressure and tiny nozzles, then they can achieve a fog that evaporates in the air.