Update on the prediction for Solar Cycle 25

In a blog post in April 2021, I outlined how Frank Donovan, W3LPL who is one of the top contesters in the USA had made a prediction for the upcoming sunspot cycle 25.

W3LPL wrote... “If the SFI persists below 90 through December 2021, then propagation should improve gradually until a solar maximum weaker than Cycle 24’s arrives in 2024.

If the SFI persists above 110 through December 2021, then propagation should improve rapidly until a solar maximum similar to Cycle 24’s arrives in 2024.

“If the SFI persists above 125 through December 2021, then propagation is likely to improve more rapidly until a solar maximum stronger than Cycle 24’s arrives in 2024.”

(SFI = Solar Flux Index)

As we have now passed December 2021, it's time to look back at the prediction. 

As can be seen from the chart above, the average solar flux for the month of December was 103. This is closest to the the middle prediction which is that solar cycle 25 will be roughly the same as the previous cycle which peaked in 2014. 

This is also very much in line with the main scientific predictions from the like .

Cycle 25 progression... This is the latest chart which shows how the solar flux is progressing against the actual prediction from NASA...

As you can see, it's ahead of schedule at the end of 2021. The big question though is will it stay like this?

Some will claim that a rapid early rise is a sign of a larger than usual solar cycle. Unless I hear something credible, I would suspect we're heading for a subdued peak like 24.

Cycle 25 is going to be good... Sometimes when these predictions about sunspot cycles come out and people speak about them being low, I think some beginners may get the impression that things on the HF bands will be terrible. The answer is that they won't. There will be loads of DX on all the HF bands up to and including 28 MHz.

What it will mean however is that the MUF (maximum usable frequency) may not get up to the 50 MHz bands, especially on East-West paths. If this isn't a priority for you then things on the HF bands will be fine.

Always remember that that predictions are just that... predictions. We'll all have to wait and see how things pan out in reality.