For decades, countless numbers of people with arthritis have claimed they know how cold the weather is based on pain in their joints. The cold weather also thickens synovial fluid, which acts as a lubricant and shock absorber. Joint pain may also be magnified during cold weather because nerves and blood vessels in the arms and legs constrict when exposed to the cold. Sensitivity to pain is heightened in cold weather, and even mild dehydration can make those with arthritis more sensitive to arthritis pain. A good way to avoid joint pain is to keep your joints from getting cold.