# Effect of humidity on temperature

When temperature changes, relative humidity changes. Imagine I have a closed room at a certain temperature; then, I blow water vapor at a similar temperature. Can a change in relative humidity induce a (small) change in temperature? If it does, would the temperature raise or decrease? I have tried to find information but all I find is about the influence of temperature on relative humidity, not the other way round.

• You are spraying water droplets into a room filled with air at a certain relative humidity. The temperature of the water droplets being sprayed is the same as that of the air in the room. Is that a correct description of what you envision? – Chet Miller Aug 19 '17 at 12:37
• Google the term "swamp cooler". – David Hammen Aug 19 '17 at 17:23

Now to your question. If the added water is already gaseous and at the same temperature, $T$ will stay constant, because the mean kinetic energy per particle is the same as before. If the water you add is in liquid form like droplets, the temperature would decrease, because some of the kinetic energy of the air is needed to evaporate the water, decreasing the mean kinetic energy.