Solar Cycle 25 Continues to Strengthen Rapidly

Discussion: The June 2022 solar activity analysis from the Royal Observatory of Belgium indicates a continued stronger-than-forecast sunspot number (Fig. 1). If the increase in sunspot number were to continue at the same pace since onset of solar cycle 25, the “standard curves” prediction method indicates an extreme solar maximum (possibly a record) would occur mid-decade. Combining that extreme scenario and the initial NASA forecast yields a “combined method” forecast also considerably stronger than the initial NASA outlook.

The number of C-, M- and X-class flares on an annual basis reveals how the onset of each of the last two solar cycles emerged. Solar Cycle 23, which was quite strong, steadily (and rapidly) strengthened the first 3 years prior to solar maximum in 2000-02 (Fig. 2).  Solar cycle 24 started slow and suddenly strengthened in 2011 before a historically minimal solar maximum in 2014. Solar cycle 25 is somewhere in-between the last two emerging solar cycles although 2022 is likely to verify at a somewhat higher value.

Interestingly, years with the most intense geomagnetic storms are not necessarily observed in a solar maximum. The most intense years for geomagnetic storms were in 1994 and 2003 (Fig. 3) when sunspot activity was in decline.

Summary: Solar Cycle 25 appears to be intensifying more rapidly than initially forecast. Based on this early stage of solar cycle 25 observations, the solar peak projected for mid-decade is likely much stronger than previously forecast. There is potential for a historic solar maximum if the current rate of strengthening continues. Despite the potential for an exceptionally strong solar maximum, the correlation to larger than normal geomagnetic storms are not necessarily expected.

Prior to Solar Cycle 25, there was concern that a “Daulton Minimum” may be emerging. The “Daulton Minimum” occurred during 1800-1830 when 3 consecutive relatively inactive solar cycles were observed. The rapidly strengthening Solar Cycle 25 implies the “Daulton Minimum” risk is lowering rapidly.

Fig. 1: The solar cycle progression – sunspot number – for June 2022.

Fig. 2: The number of annual C-, M- and X-class flares since 1997.

Fig. 3: The number of annual number of days with geomagnetic storms each year.