Solar Cycle 25/26 Update

A bit ahead of being a six month update; my last update was last December 28th, but there's a couple of things that are interesting to note.  

To begin with, though, the regular "formalities" are that most of this information comes from a video talk delivered to a group I belong to of VHF ("six meter band") aficionados on groups.io, called the Front Range 6 meter group.  Originally a group along the "front range" area in Colorado, they now have members from around the world.  As with every such talk I've watched, it's delivered by Dr. Scott McIntosh, formerly with the National Center for Atmospheric Research (NCAR).  In the last year, Scott has moved to Lynker Space in the private sector.

The first thing is that cycle 26 has begun so we have two cycles in progress now and will continue that way until cycle 25 dies completely.  In December's talk, I used this screen capture from his previous talk showing that he had evidence that cycle 26 has begun.  Perhaps the biggest improvement to forecasting Dr. McIntosh has introduced is a way of identifying the exact time when the new sunspot cycle starts.  That's noted when new sunspots happen at very far northern or southern latitudes and have a magnetic polarity opposite the current cycle.  The diagonals (red and blue) show the progress of the spots in each cycle and the slopes show how the spots progress from higher to lower latitudes as the cycle progresses.  The four belts vertically  are implying the latitudes of the activity, with the solar equator in the middle.

A regular inclusion in these updates is the SSN or Smoothed Sunspot Number, as tracked by the NOAA Solar Cycle Progression chart from their web site. 

A new feature in this plot is colored bands in the future, showing 25, 50 and  75% predicted ranges.  You'll notice that the absolute peak of cycle 25 occurred during 2024.  There were some days with very high solar flux in '24: the highest peak was in August as shown here: each black dot is one month, and the last dot in this plot is March's number (the plot shows "updated 2025-04-02" bottom right).  I was regularly in the shack monitoring 6m activity much of end of '24 and saw something I've never seen in my life, spots of ham stations in Alaska being reported within a few hundred miles of me.  I've never heard an Alaskan signal make the last hop to Florida (on 6m), although a friend in Tennessee heard one, one time.  Both of us consider that a once in a lifetime moment.  It was last December 1.  We haven't had solar flux numbers like that since then but the highest Solar Flux measured in cycle 25 was in August of 2024.  

Finally, a plot I’ve shown regularly which shows the Smoothed Sunspot Number (SSN) for the last five cycles back to 1976. I like this plot because it’s my ham radio biography in one plot. I was first licensed in February 1976 (the blue curve), so every cycle I’ve been through is on this plot (and I was a shortwave listener for the cycle before that).  The plot is posted to Space Weather News (bottom of the page) but is created by a separate site, Solen.info.  I've regularly reported that while cycle 25 has been stronger than cycle 24, pink in this plot, that was the weakest cycle in the last hundred years, but 25 hasn't exceeded cycle 23 once.  So stronger than 24 is better than equaling it, or being weaker than it, but it's a long way from a good solar cycle.

It still hasn't exceeded cycle 23, but it equaled 23 for one graph square and then the recorded cycle 23 SSN out performed it and stayed higher than cycle 25. 

And just between us geeks, I absolutely hate the way the horizontal axis is labeled on this.  It divides the scale into groups of 10 "Months after cycle start", which is fine, but then notice that between numbers, like from  50 to 60 or any group of 10, it has SEVEN minor divisions.  Who on Earth would think to divide 10 months into SEVEN lines?  10/7 of a month?  Why not 10 minor divisions so each line was one month?  Or even five, so each one was two months?

Is there no chance of hearing Alaska down here again - in this cycle?  One thing  that's in our favor is that cycle 25 is looking very asymmetric.  We thought it was peaking 20 months ago around 40 months into the cycle, but after remaining at relatively low SSN, has been moving toward a peak farther out (in time).  What we don't know is how much longer it will stay around where it is now.  The second plot, on the cycle's progress pretty much predicts the SSN will be lower by 2026 after perhaps another quarter or half year around where it currently is.

To borrow that wonderful quote from physicist Niels Bohr, “Prediction is very difficult, especially if it’s about the future.”