It is time for my monthly update of the Sun’s ongoing sunspot activity, using the update that NOAA posts each month to its own graph of sunspot activity but annotated by me with extra information to illustrate the larger scientific context.

The activity in May was shocking in that it completely contradicted all expectations by everyone in the solar science community, with the Sun’s sunspot count changing in a way that was somewhat unprecedented. The graph below makes this very clear:

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, then predicting that solar maximum is over, and the ramp down to minimum had begun

Activity in March and April seemed to more or less match that new prediction. The activity in May, just posted this week, is however completely beyond any prediction. I cannot find any past solar maximum that saw this much of a sudden steep drop in sunspot activity.

Past ramp downs from maximum have always tended to stretch out more slowly than the ramps up to maximum. Here however the Sun has done the opposite, its activity crashing in only one month.

Does this mean solar minimum is just around the corner? Hardly. Just as the Sun’s sunspot activity dropped so unpredictably in May, it could increase exponentially in June. Moreover, even with this drop there is still no reason at this moment to assume the new 2025 prediction of NOAA’s scientists is right either. As you can see by the green, blue, and red lines (indicating past predictions), their track record has been generally poor in the past two decades. It is still entirely possible that the Sun is presently in a double-peaked maximum (as seen in the previous maximum), and that we shall see a new rise in the coming months.

Or not. As I have said now repeatedly for years, no one yet understands the fundamental processes in the Sun’s magnetic dynamo that cause the magnetic field to flip polarity every eleven or so years and thus produce this cycle of sunspots. Nor do we understand why sometimes this cycle ceases for decades, producing few sunspots at all. And without that understanding, no prediction by anyone has much chance of being reliable.