Different climatic conditions have an important influence on photovoltaic module degradation. As such, degradation analysis of photovoltaic modules from diverse geographical locations are of great interest. Evidence indicates that not only degradation but also failure mechanisms are location dependent. This book looks into research undertaken to investigate the mechanisms of degradation, the causes of degradation, how a module degrades and how the degradation can be avoided. It is observed that despite the fact that panels are designed to operate in outdoor environment, numerous cases do exist whereby the panels degrade physically, in various ways and consequently exhibit either total failure, diminished performance or just physical manifestation of wear. Apart from manufacturer defects, user ignorance on installation and usage also contributes to reduced life span of some panels.