text: Purely in terms of numbers, sunspots vary with a cycle that is about 11yrs on average, known as the Schwabe cycle. One can't be any more precise than "about 11yrs" as the cycle varies somewhat, primarily due to fluctuations in the magnetic field of the sun. A more "geeky" answer is 22yrs, however (the Hale cycle), as the magnetic field of the sun reverses polarity each Schwabe cycle and so it takes 22yrs to "get back to where we started". This makes no difference to mere humans, as sunspots look the same to us in each phase, but if you were Superman with super-vision perhaps it would!