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This paper describes a methodology used to evaluate pyranometers and reference cell performance in relation to solar overirradiance (OIR) events. By definition, these events are characterized when global horizontal irradiance (GHI) exceeds the extraterrestrial horizontal irradiance (ETH) due to cloud enhancement (CE) effects (e.g. scattering, reflection, cloud lense augmentation). Evaluation metrics are proposed to assess relevant features of the events such as uncertainty, event identification, and response time. The metrics were validated with high standard radiometers deployed at the Solar Energy Research Laboratory Fotovoltaica/UFSC in Florianópolis, Brazil. The results were checked against solar radiometers’ specifications, and sensors were analyzed according to their performances. An ISO outdoor calibration, as well as a system uncertainty analysis and data response time evaluation, were performed, to assure results reliability. In addition, two extreme overirradiance (EOIR) events were evaluated separately, and seasonal occurrence of the energy fraction of overirradiance events was assessed and discussed.