It doesn't read the temperature of the air. Some engine also use an intake air temp sensor.
The Mass Air Flow sensor uses a hot wire to measure the air mass. The wire is kept at the same temperature, and the current needed to maintain the temperature is used to determine how much air is flowing past it. Most of the time it works very well and is extremely responsive. The vane air flow meter which was in common use prior to the common use of a MAF sensor was not nearly as responsive. The vane air flow meter was a flap (or vane) that hung out into the airflow. As the airflow increased, the flap moved. The flap was attached to a reostat which provided a value for the processor to determine the airflow. The mass of the vane or flap kept it from being very responsive.
