They use evaporative cooling on days where it is over 85f
Microsoft’s data centers currently use adiabatic cooling, which relies on outside air to cool down temperatures inside. It’s a system that uses less electricity than air conditioning and less water than cooling towers. But when temperatures rise above 85 degrees Fahrenheit, outside air isn’t very helpful. At that point, an evaporative cooling system kicks in, which uses water. It works like a “swamp cooler” — cooling the air by pushing it over or through water-soaked screens.