Usually, times of the greatest solar activity are correlated with greatest auroral activity.
Auroral activity is most intense when the sun produces expulsions of plasma called Coronal Mass Ejections (CMEs). Most of these are directed away from Earth, but one out of ten or so are directed towards Earth by random chance. When these walls of plasma impact the magnetosphere they set the stage for producing brilliant aurora in the polar regions. During sunspot maximum, hundreds of these CMEs are produced every month, so the odds that a few of these each week will produce strong aurora is very high if you live at latitudes above about 50 degrees. If you live at lower latitudes, say in the Lower-48 States of North America, then you will need a particularly severe CME event to light up your skies. These 'Kp=9' events during solar maximum can happen every month or so, but perhaps as few as once a year during sunspot minimum conditions. Between 2003-2004, we had three of these events, and they all produced aurora visible as far south as Maryland and Georgia.
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