A fan does not actually reduce the temperature of the surrounding air. Instead, it helps create the sensation of cooling by increasing air movement and promoting evaporative cooling.
When a fan blows air across your skin, it speeds up the evaporation of moisture from your skin's surface. As this moisture evaporates, it carries away some of the heat from your body, creating a cooling effect. This is why you often feel cooler when there's a breeze or when you're in front of a fan.
However, it's important to note that the actual temperature of the air in the room remains the same. The fan doesn't change the air temperature, but it can make you feel more comfortable by increasing air circulation and facilitating evaporative cooling on your skin.
In hot environments, combining a fan with other cooling methods, such as air conditioning or using a damp cloth on your skin, can further enhance the cooling effect.