A wind turbine rotor produces power from the torque generated by the rotor blades. This torque arises from forces on blade elements which in turn are the consequence of pressure differences on each side of the aerofoils. (source)
Thermodynamic theory states that when the pressure of a gas does work, the gas cools down. In this case the air pressure does work on the rotor blades. Microscopically, the air molecules impacting the blade on its high pressure side move the blade and transfer kinetic energy onto it which lowers their average kinetic energy and decreases the temperature of the air.
Mathematically there should be a temperature drop at the rotor plane although it is probably quite small. What do you say?