Solar Minimum
Definition
The quiet trough of the solar cycle, with few sunspots and few solar eruptions.
In plain language
At minimum the Sun's surface can go weeks without a single spot. Big storms become rare โ but high-latitude auroras never stop, fed by fast wind streams from coronal holes.
The science
Solar minimum features minimal sunspot activity and weak CME rates, but recurrent high-speed streams from long-lived coronal holes still drive moderate geomagnetic activity, often recurring at the ~27-day solar rotation period.
Why it matters for aurora viewing
Under the auroral oval, minimum years are still good; far from it, expect long waits between shows. Coronal-hole streams are minimum's best friend.
See this in action on tonight's data.