Most people complain that their pain increases due to the cold, rainy, damp weather but research has shown it’s not that. Scientist have not come to a full agreement that weather causes pain but there are some theories. One of the main theories scientist have is the change in air pressure. What is affecting most of the people is the barometric pressure, which is weight of the atmosphere that surrounds us. The barometric pressure often drops before the bad weather even occurs. The lower air pressure pushes less against the body, allowing tissues to expand -- and those expanded tissues can put stress on the joint. The best way to explain it is the body can either expand or contract based on outside pressure changes. Those changes are going to affect how pain is signaled in your body.