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The K7RA Solar Update


The average daily sunspot number for June, 2023 was the highest in 21 years, according to

From a July 3 email alert from

"SUNSPOT COUNTS HIT A 21-YEAR HIGH:  It's official:  The average sunspot number in June 2023 hit a 21-year high.  Solar Cycle 25 has shot past its predecessor, Solar Cycle 24, and may be on pace to rival some of the stronger cycles of the 20th century."

Could we see another Cycle 19, the biggest in recorded history, even back before the birth of radio?

Not too long ago, we heard that this cycle should peak in summer 2025.  Later that was revised to 2024.  Now I am seeing occasional references to a cycle peak at the end of this year.  

From my own records, average daily sunspot numbers for April through June 2023 were 93.7, 125.8 and 143.9, a nice upward trend.

Some popular news outlets seem confused by the difference between sunspot number and number of sunspots, and have quoted another higher average.

Here is the difference.  If they are just counting the total number of sunspots for the month, this is far different from average daily sunspot numbers.  The sunspot number is somewhat subjective, but it gets ten points for each sunspot group, and one point for each sunspot in those groups.

But I stand by my numbers.  They are all from NOAA and appear at the end of each bulletin.

But they may be referencing International Sunspot Number, which may be different from the SESC numbers from NOAA.

Here is an example of confusing sunspot numbers with number of sunspots:

This one is also confusing, saying there were 163.4 sunspots in June.

But what does this mean?  It could be either 163 or 164 sunspots, but not a fractional number, unless it expresses an average.  The minimum sunspot number is 11.  This would be one sunspot group containing one spot.  They are always whole, not fractional integers.

There was one new sunspot region (group) on June 30, three more on July 1, one more on July 2, another on July 4, and one more on July 5.

Sunspot and solar flux data again this week did not track together. Average daily sunspot number declined from 170 to 126.1, while average daily solar flux rose slightly from 160.3 to 164.5.

Geomagnetic indicators were lower, with average daily planetary A index declining from 10.7 to 7.3, and middle latitude averages from 9.9 to 8.

Predicted solar flux is 155 on July 7, 150 on July 8 to 10, then 155 on July 11, 160 on July 12 to 13, 175 on July 14 to 18, 170 on July 19 to 21, 160 on July 22 and 23, 155 on July 24 and 25, 160 on July 26 and 27, 165 on July 28 and 29, then 170, 170 and 165 on July 30 through August 1, 155 on August 2 to 6, then 160, 165 and 170 on August 7 to 9, and 175 on August 10 to 14.

Predicted planetary A index is 5, 12 and 8 on July 7 to 9, 5 on July 10 and 11, then 20 and 30 on July 12 and 13, 8 on July 14 to 22, 5 on July 23 to 30, 8 on July 31 through August 1, then 5 on August 2 to 4, 12 and 8 on August 5 and 6, then 5, 20 and 30 on August 7 to 9, and 8 on August 10 to 18.

Note those big numbers are about one solar rotation apart, which is about 27.5 days.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for July 6, 2023 from F. K. Janda, OK1HH.  When the current 25th solar cycle began in December 2019, solar astronomers thought it would be a weak cycle similar to its immediate predecessor, solar cycle 24.  But now we have a twenty-one year peak.  And we expect a continued increase for about two more years.

The misfortune is that ongoing global changes are reducing the ionization rate of the ionosphere.  Yet the current conditions for shortwave or decameter wave propagation do not match the amount of solar activity - they are worse.

But that's not all.  Not only is solar cycle 25 likely to rival some of the more powerful cycles of the 20th century, but we're likely to see even more powerful solar flares and magnetic storms.  History repeats itself cyclically, and we need only think of the great Halloween storm of 2003, including the strongest solar flare ever recorded in X-ray (X45).

The giant sunspot group AR3354 (only about four times smaller than the giant sunspot group of early September 1859) made its last appearance on July 2 with an X-class flare.  Two days later it eclipsed.

We won't lose the source of the stronger flares, however – the growing AR3359, with its Beta-Gamma magnetic configuration, crossed the central meridian toward active western longitudes on July 6 and will continue to grow.  With its predicted higher activity, we could see an increase in the Earth's magnetic field activity as early as the middle of next week.

Tamitha Skov, from July 1.


Stormy weekend?

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For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service at .  For an explanation of numbers used in this bulletin, see .

Also, check this article from September, 2002 QST:

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Sunspot numbers for June 29 through July 5, 2023 were 112, 187, 119, 126, 117, 121, and 101, with a mean of 126.1.  10.7 cm flux was 162.2, 158.6, 165.5, 170.2, 173.2, 167.2, and 154.6, with a mean of 164.5.  Estimated planetary A indices were 17, 8, 5, 5, 5, 4, and 7, with a mean of 7.3.  Middle latitude A index was 13, 8, 6, 8, 7, 5, and 9, with a mean of 8.



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