Abstract: A resistance spot welding monitoring system includes a plurality of sensors coupled to a resistance spot welding system to receive welding data produced during a welding operation. The monitoring system further includes a nugget prediction system. The welding data is indicative of welding parameters used to produce the weld nugget. The nugget prediction system retrieves the welding data and predicts a nugget size based upon the welding data received from the plurality of sensors. Additionally, the nugget prediction system generates a nugget size signal. The monitoring system also includes an indicator that receives the nugget size signal and notifies an operator of a predicted nugget size.