Feeling warm and cool breezes - how does it work?
You have many different types of sensors in your skin; you probably feel the pressure of the air moving past your hand in addition to the temperature.

The temperature increase in your hand due to collisions isn't very significant, you have to be going at really high speeds to encounter that phenomenon (spacecraft reentry would be an extreme example, for example see this wikipedia page).

Temperature changes due to evaporation are probably most significant (this is why even warm air blown from a fan can feel cool, especially if you are perspirating), as well as the temperature of the outside air around your hand compared to the air inside the car.