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Sunspot update: Activity rises in September but not significantly

Another month has passed, and it is once again time to post my annotated graph of NOAA’s monthly update of its graph that tracks the number of sunspots on the Sun’s Earth-facing hemisphere. The new graph is posted below, with several additional details to provide some larger context.

Last month we saw a drastic drop in August of sunspot activity, suggesting that the next maximum might possibly have been reached, though many months earlier than predicted. This month’s graph below, which shows an increase in activity in September but still well below the highs seen in June and July, strengthens that conclusion.

September 2023 sunspot activity
The graph above has been modified to show the predictions of the solar science community for the previous solar 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.

The increase in sunspots in September was relatively small, and kept the count well below previous months. Still, the count continues to well exceed the prediction, as indicated by the red line, as well as that prediction’s margin of error, as indicated by the gray curve.

Last month I said this:

The steep drop in activity in August … suggests that we might possibly have reached solar maximum, and will now see several years of up and down fluctuations (as happened during the past maximum), but no great increase matching the past high maximums from the 20th century.

The small rise in September suggests this conclusion could be correct, and that we have reached solar maximum which will continue for the next few years as a period of monthly rises and falls while generally maintaining a steady plateau.

Or not. It is dangerous to put any faith in any prediction relating to this sunspot cycle. The Sun does what the Sun wants to do, and since we don’t understand why it does it, predicting what it will do next is usually a mostly fruitless effort.

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  • Phill O

    Thanks for the insights Bob!

  • BLSinSC

    With the increase in sunspots in Sept we’ve seen some nice weather — slightly warmer and dryer — these periods USED to be called “Indian Summer” but with the lunatic leftists running amuck I guess we are forbidden to use that term! SO, I have to say that I am ENJOYING my INDIAN SUMMER and getting a lot of yard work, home maintenance, and GOLF!

    Let the doomsayers shriek – the SUN RULES our Earth!!

  • Phill O

    Indian Summer is now here in Alberta. Some very warm days forecast for next week.

    The northern sunspots continue their trend towards the equator; into October.

    We will see, if those who forecast that this signals the end of this cycle, are correct.

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