This chapter discusses solar forecasting research and practices from a philosophical viewpoint. Although solar forecasting is a science and engineering subject, the reader can benefit greatly from the philosophical thinking tools presented in this chapter. No different from carpenters needing hammers and saws, or surgeons needing lancets and forceps, thinking tools are needed by philosophers to reliably and gracefully approach what confronts them. Thinking tools are fundamental to reasoning, understanding arguments, problem solving, and decision making, and it is on this account that they must be placed among the most useful domains of knowledge that can advance solar forecasting research.