A data logger is an electronic device that records data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors. It is generally small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors.

One of the primary benefits of using data logger is the ability to automatically collect data on a 24-hour basis. Upon activation, data logger are typically deployed and left unattended to measure and record information for the duration of the monitoring period. This allows for a comprehensive, accurate picture of the environmental conditions being monitored, such as air temperature and relative humidity.