A method and system for tracking variable conditions using radio frequency identification (RFID) are disclosed. In embodiments of the present invention, an RFID sensor tag is used to measure a condition. The condition can be any measurable condition such as location, temperature, humidity, pressure, time, date, inertial measurements, etc. Variable data representing the measured condition is read from the RFID sensor tag in order to track the measured condition. The variable data can be read from RFID sensor tags in addition to reading tag identification data from RFID tags, so that the variable data can be associated with tag identification data.