Recognizing the critical role of calibration and measurement uncertainty in meteorological measurements, and getting increased demand from the Members for supporting them to improve their capacities for calibrating the measuring instruments, WMO has developed this Distance Learning (DL) course on calibration to address gaps in competencies and capacity across WMO Members. By leveraging the WMO Competency Frameworks for observations, instrumentation, and calibration, this course aims to provide online training for the Members’ staff dealing with calibration of instruments and their use in measurement sites and processes.