Sunspots are darker, cooler parts on the Sun’s surface in the region of the photosphere. It is a temporary phenomenon where it can last anywhere from a few days to a few months. Although sunspot is the cooler part of the Sun’s surface, it’s temperature ranging from 2000°C to 4000°C. However, it considers cool in comparison with the temperature of the photosphere, which is about 5500°C.
Sunspots are only dark in contrast to the bright face of the Sun. If we put the average sunspot anywhere in the night sky, it would about as bright as a full moon. Sunspot form due to strong magnetic field lines coming up from within the Sun through the solar surface. The magnetic field lines are often tangle, cross and reorganize where it can cause solar flares and big storms called coronal mass ejections.