Sunspot update: Ramp down to the next sunspot minimum now seems certain
NOAA today posted the monthly update of its graph showing the sunspot activity on the Earth-facing hemisphere, adding the data collected during September 2026. I have posted this updated graph of sunspot activity below, annotated further to make clear the larger scientific context.
It shows that September’s sunspot activity, indicated by the green dot, was at the lowest level since February 2022, when the ramp up to solar maximum had been going on for about two years. Now, the ramp down is clearly occurring. Until this month the Sun’s activity had fluctuated enough to leave room for the possibility that activity could rise again to form a second peak at maximum, as happened in the previous maximum.
The drop in September almost certainly precludes the possibility of double-peaked maximum this cycle.
The graph above has been modified to show the predictions of the solar science community for both the previous solar maximum as well as the ongoing maximum. The green curves show the community’s two original predictions from April 2007 for the previous maximum, with half the scientists predicting a very strong maximum and half predicting a weak one. The blue curve is their revised May 2009 prediction. The red curve is the new prediction, first posted by NOAA in April 2020. At the beginning of April 2025 NOAA’s panel of solar scientists added the purple/magenta curve line, predicting that solar maximum was over, and that the ramp down to minimum had begun.
That ramp down appears to now be definitely occurring is a confirmation of the April 2025 prediction of that ramp down by NOAA’s panel of solar scientists. At the time I thought they were premature. In this case however they got the beginning of ramp down correct.
The Sun is still confounding them, however. Note how the ramp down is dropping faster than their prediction. Based on its present pace, minimum could occur as early as 2028, though more likely around 2030. That would make this one of the shortest cycles ever recorded, ten years long or less. Past short cycles corresponded with high activity. This short cycle however corresponds to weak activity.
In other words, the Sun does what it wants to do, and we really do not yet understand why.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
It would be interesting to see the integral under the peaks and evaluate how those numbers progress over time.