Why does it feel warmer outside than it actually is in humid weather?

Question

I know of the term heat index, which relates to what it feels like outside. My question is, why do we feel like the temperature is higher, when in fact it isn't?

Answer 1

Our bodies cool down by sweating.  The water in the sweat absorbs the heat from our bodies and evaporates, carrying the heat with it.  When it's humid out, because there is more water in the air, it's harder for sweat to evaporate off your skin, so the heat doesn't go anywhere.

Answer 2

When it's humid your sweat doesn't evaporate as fast. When the humidity is low your sweat evaporates faster carying heat away from your body.

Answer 3

Because humid weather reduces the efficiency of the body's cooling mechanism, which is sweating, when the humidity is higher the air has that much less room to absorb additional moisture.