Monday, July 25, 2022

Solar Cycle Progression Update

It has been since February that I've posted plots like these, an update to solar cycle 25.  For those of us watching solar activity and experimenting (that is, playing) with it regularly, it has been rather interesting.  

Both plots are pretty similar, but emphasize different aspects.  First off is the Cycle 24/25 plot from the National Oceanographic and Atmospheric Administration, NOAA, and their Space Weather Prediction Center.  This plot shows the sunspot numbers and you can read numbers directly by hovering your mouse over one of the points on the chart - on the website linked there, not this graphic.

There is a very obvious separation between the actual values (smoothed values as the purple line and monthly values as the black dots on that line.  Note this is sunspot number and not the 10.7 cm solar flux.  For the second to last dot, this past May, the predicted value was 39.7 while the observed sunspot number was 96.5; almost 2-1/2 times the predicted value.  The last dot, June's, was substantially lower in measured at 70.5 while the predicted number was a bit larger than May's at 42.8.  There's always up and down variation in these plots, but the trend has been above the predicted values since cycle 25 started. 

The next plot is an update to the second plot in the February post, the one I jokingly refer to as my "ham radio autobiography" because these are smoothed sunspot plots of every solar cycle since 1976, the year I got my first ham license. 

You'll note that almost without exception every data point of every cycle is lower than its predecessor since 1976, the top curve (blue).  Except that short gray trace that shows cycle 25 advancing in from the bottom left corner.  Every single point in cycle 25 is greater than or equal to the previous cycle, shown here in pink.  This plot is from Space Weather News, which says it's from a site called, but I don't see it at that link.

Looking at the bottom left corner where Cycle 25 is coming in shows the bigger picture that 25 is doing better than cycle 24, and the previous plot showed it's doing well above predictions.  The thing to bear in mind is that Cycle 24 was the weakest in a hundred years, so doing better than that isn't necessarily saying it's going like gangbusters.  While I think the big picture is a bit more optimistic than it was almost six months ago, that discussion concluded with a plot from Dr. Ron Turner of ANSER Research Institute in Virginia, via, showing how the beginnings of 24 and 25 overlap well.  Dr. Turner's conclusion wasn't that 25 was going to match 24, just that it's too early to predict something much better based on the early numbers. 

I think we're in a better place now, but not at a point where we can confidently say 25 will be much stronger or not.  In another year?  Probably.  That plot shows us being at month 24 and by month 36, cycle 24 was close to its peak. 

I've noted that there have been higher solar flux numbers in the last month or so than I've seen in quite a while.  At some point late last week I saw a solar flux over 170, and the solar flux data archived at shows it has happened a few times on a cyclic basis.  The VHF band I hang out on the most, 6m, has had its moments of really great propagation, but I haven't really heard any of those since June.  


  1. The DX cluster I watch has the current solar numbers on their header, and when I saw it was at something like 169 the other day I about fell out of my chair!

  2. I have great fun telling the Climatistas that the decline in solar activity is due to all the solar energy panels.

    1. Good thing that I didn't have a mouthful of coffee when I read this. It would have come out of my nose.

    2. Honestly, I wish I'd thought of it!