Solar minimum is the period of least solar activity in the 11-year solar cycle of the Sun. During this time, sunspot and solar flare activity diminishes, and often does not occur for days at a time. The date of the minimum is described by a smoothed average over 12 months of sunspot activity, so identifying the date of the solar minimum usually can only happen 6 months after the minimum takes place. Solar minima is correlated with changes in climate.[citation needed]

Solar minimum is contrasted with the solar maximum, when hundreds of sunspots may occur.