The MDL-2009 data recorder has been designed to perform measurements necessary for windiness audits preceding construction of wind power plants. Besides registering measurement data connected with the speed and direction of wind, the device can also be used to register air temperature, humidity and atmospheric pressure. The recorder is equipped with 5 inputs for anemometers, 4 analogue inputs to connect wind direction meters and dedicated analogue inputs for registration of other weather parameters. The measurement data are saved in the form of a text file, which can be imported to a given program dedicated for analysis and estimation of wind energy, or to a typical spreadsheet. An integrated GSM modem enables wireless transmission of registered data and remote configuration of the MDL-2009 device. Programming the recorder is user-friendly, whereas a series of available functions and parameters ensure high flexibility of configuration. The system is delivered together with an external casing resistant to weather conditions, a gel accumulator and a solar panel.