According to TCM (Traditional Chinese Medicine) 5 Element Theory (the basis of acupuncture, acupressure etc) there are 5 major organ systems. Each system has an associated colour, part of the body, emotion, season, pathogen (the state it really hates) etc. Each organ is at its most vulnerable during its corresponding season, meaning that the emotion linked with it becomes more apparent.
Autumn is associated with the Lung system, and Lung's emotion is grief. From an acupunct