How long is an average sunspot cycle?

The sunspot cycle, also known as the solar magnetic activity cycle, is a nearly periodic variation in the Sun's activity and appearance. On average, this cycle lasts for about 11 years, during which the number of sunspots waxes and wanes. Amateur radio operators pay close attention to this 11-year cycle because high sunspot numbers correspond to increased solar ultraviolet radiation. This radiation heavily ionizes the Earth's upper atmosphere, which dramatically improves high-frequency (HF) skywave propagation for long-distance communications. Distractors like 5, 7, or 17 years are arbitrary numbers that do not align with observed solar behavior.