Every approximately eleven years, the Sun produces a “cycle” of sunspot activity. At the very lowest point in this cycle, there are few, if any, sunspots observed. Such a lack of sunspots can last for weeks. During the peak of the sunspot cycle, there can be a multitude of sunspots, ranging in size. This cycle is known as the sunspot cycle. It is caused, in part, by the magnetic activity within the Sun. Every eleven years, the Sun’s magnetic polarity flips–the north becomes south, the south becomes north. This is normal. Every twenty two years, then, the Sun goes through one full magnetic flip cycle. The flipping seems to coincide with the timing of solar cycle maxima. When it flips, we know about where we are in the eleven-year cycle. The magnetic polarity of the Sun appears to be in the process of reversing, over the next few months. If so, then we’ve pretty much reached the sunspot cycle maxima for Cycle 24. Observers note that this cycle is quite a bit less active than the last few eleven-year cycles.
A video that talks about this reversal is here:
More information on the Sun and the cycle, radio propagation, and related topics: