Joint pain when it rains is the most common clinical condition and a common symptom that can occur in many rheumatic diseases. Patients with arthritic symptoms of rheumatism are 90% sensitive to climate change. When it rains and rains on cloudy days, when the climate changes suddenly, and when the seasons change in autumn, winter and spring, the pain or swelling in the joints of patients can be significantly increased. The reason for painful joints on cloudy or rainy days is that the joints and surrounding blood vessels of patients with rheumatism are not functioning properly, and vasodilation and contraction are slow and inadequate, and the rise and fall of skin temperature is sluggish. Therefore, patients are unable to adapt to changes in climate, and when the humidity is high, it will stimulate the patients and increase the sensitivity of the nerves in the joints. When it is cold, blood flow slows down, the level of adrenaline in the blood rises, and globulin coagulates, which increases the viscosity of synovial fluid in the joint cavity and increases the resistance to joint movement. Decreased air pressure during cloudy, windy, or rainy days can also cause fluid to accumulate in the interstitial spaces of joint tissues, resulting in a relative increase in intracellular pressure and pressure in the joint cavity, which can lead to increased joint pain and swelling. That is, it is a non-specific manifestation that occurs due to inflammation of the joints leading to different degrees of pathological changes in the joints and surrounding tissues and the body’s inability to adapt to climate change, which can occur in a variety of rheumatic diseases clinically. However, we should note that this phenomenon is not unique to rheumatoid arthritis. Patients with joint pain on rainy days should go to a specialist in time for further examination to clarify the specific cause.