Defect and safety inspections were performed on about 56,000 photovoltaic (PV) modules representing 257,000 modules of multiple technologies (mono-Si, poly-Si, a-Si, CdTe and CIGS) aged between 1.3 and 26 years, and operating in four climatic regions (hot-dry, temperate, cold-dry and hot-humid) of the United States. The number (or percentage) and types of defects and safety failures primarily depend on technology, design, installation, climate and age. The results presented in this paper will provide insights into the dominant types of defects and safety failures which are commonly found in multiple climates and that are specific to each climate.