Young people’s knee joints are sore when it rains, mainly because they are considered to have underlying disorders of the knee joints, which may include old injuries, chronic synovitis and arthritis. Physical therapy, hot compresses, medication and surgery are needed. 1. Obsolete injuries: Obsolete injuries include soft tissue injuries, lateral collateral ligament injuries and cruciate ligament injuries, etc. The drop in temperature during rainy days will lead to cold knee joints, and the drop in air pressure will affect the blood circulation of the whole body, which will lead to aggravation of obsolete injuries of the knee joints, and produce corresponding pain symptoms, which requires physical therapy and hot compresses. Serious conditions require minimally invasive surgery arthroscopic surgery. 2. Chronic synovitis: Chronic synovitis is usually not obvious, but when it rains, the synovial ischemia is aggravated because of the weather changes, and pain is manifested. Physical therapy, hot compresses and non-steroidal drugs such as Loxoprofen sodium and Celecoxib are needed. 3. Arthritis: Traumatic arthritis of the knee joint, rheumatoid arthritis and other immune system disorders can cause swelling and pain in rainy weather. Medications such as ibuprofen and celecoxib are needed. In severe cases, minimally invasive arthroscopic surgery is needed to clean out the joint cavity. It is recommended that young people with this symptom go to the hospital in time, after a clear diagnosis to take active treatment, to prevent the underlying disease for a long time, causing irreversible damage to the knee joint, which will lead to the emergence of knee pain and dysfunction and other adverse consequences.