A method and system for performing quality control checks upon weather data are provided. The weather data includes information pertaining to a plurality of weather parameters. The quality control checks may identify inaccurate weather parameters or be used to rank weather data sets. The quality control checks include hourly, daily, and forecast quality control checks performed upon hourly, daily, and forecast weather parameter data. The method and system may exclude the inaccurate weather parameters identified from a reasonable weather database. The method and system may determine reasonable or approximate weather parameters that approximate the actual weather parameters. The system may rank a plurality of weather data sets based upon the accuracy determination. The reasonable weather data or the weather data ranked as the most accurate may be used to calculate energy or cost savings for building energy conservation measures.