The present study introduces a new procedure to analyze and design wind farms maintenance plans, based on analysis of variance, that can be directly implemented by the own operator. This methodology, based on a one-way analysis of variance study of weather variables and wind turbine working conditions, allows to define the exact operating range at which each of the most frequent errors in wind farms used to happen. Typically, most frequent errors, like freezing of anemometers, excessive orientation time errors, brake shoe excessive temperature, emergency stop, and asymmetric currents, appear under certain weather, temperature, and wind velocity conditions, in such a way that they can be modeled as a function of wind velocity and wind direction. In a similar way, other analyzed errors, such as starting problems and errors in current phase sequence, showed a tendency to appear under specific wind orientations.