In simple terms, water is more than 20 times more efficient in transferring heat energy than air. The more moisture in the air, the more heat energy transmitting matter there is per volume, the more you feel heat or cold.
That is why it can feel less cold when temperatures fall lower than 0 degrees Celsius (32 Fahrenheit): Most of the moisture in the air becomes solid and falls to the ground.
Don't we all love those wet cold days?
