Within the framework of Chinese concepts of health, the climatic environmental factors that may act negatively on health are: Wind, Cold, Heat (Fire), Dampness, Dryness and Summer Heat, the last being an entirely external influence. When the body is weakened by any imbalance, or by predisposition, such climatic phenomena can invade it as a pernicious influence. The body then experiences a conflict between such influences and normal Qi and protective Qi. Illnesses generated by such influences usually appear without warning and are characterized by aversion to the invading influence. Symptoms arise from efforts of the body to expel the influence.
The pernicious influences can invade the body from the outside, as an external influence manifesting as an acute illness. They can also emerge internally, in which case the appearance of symptoms may be more gradual and is usually associated with more chronic illnesses. Both sets of influences mimic climatic conditions and are treated accordingly. However, unlike in Western medicine, it is not the cause that determines the treatment. The treatment is always for the condition itself. The pernicious influence, as a cause, is unimportant.