As Earth’s water evaporates, water vapor in the atmosphere condenses. Evaporation and condensation are opposites, and they happen at the same time. The comparison of condensation and evaporation Is relative humidity. For example, 50% relative humidity means that the number of water molecules condensing each second is half of the number of water molecules evaporating each second. One-hundred percent relative humidity means condensation equals evaporation. The amount of water vapor in a given volume of air at 100% humidity depends on the temperature. This is because the warmer the water is, the greater the evaporation. This means that the air must have a greater amount of water in it for condensation to equal evaporation.