Sunspots are temporary dark spots on the surface of the Sun. They appear darker than the surrounding areas because they are cooler, with temperatures around 3,000 to 4,500 degrees Celsius, compared to the Sun's surface temperature of about 5,500 degrees Celsius. Sunspots are caused by magnetic activity that inhibits the flow of heat from the Sun's interior to its surface. These spots can vary in size and can last from a few days to several weeks. The number of sunspots increases and decreases in an approximately 11-year cycle, known as the solar cycle. This cycle affects solar activity, including solar flares and coronal mass ejections.