Humidity keeps us hot

On hot and humid days, you may experience sticky and overheated skin, and the air can feel heavy.

This is because high humidity (the amount of water moisture the air possesses) can make it difficult to get rid of excess body heat through sweat. Usually, sweat on our skin evaporates into the air, cooling our skin. But humidity prevents the sweat from evaporating, as the high moisture content in the air can't absorb much more.