Defying Expectations, Solar Activity Returns to a 23-Year High

Defying expectations, solar activity is back in a big way, with the number of sunspots counted on the Sun’s surface last month reaching levels not seen in nearly 23 years, more than twice the number predicted by previous forecasts. This newfound activity signals not only that the Sun is well within this cycle’s solar max, but also that the multi-decade lull in solar activity may be coming to a close.

The month of August saw an average daily count of 215.5 sunspots, peaking on August 8 when there were 337 spots observed on the Sun’s surface, a count not seen since March 2001; this well exceeds the prediction made by NOAA’s Space Weather Prediction Center in 2020 of a daily count of only 107.8 for the month—just under half of what was actually recorded.

The high amount of activity seen over the course of this cycle has defied earlier predictions, with calls for a mild season being met instead with higher levels not seen since the turn of the millennium. Since the mid-twentieth century, each 11-year cycle has seen declining solar activity, leading many researchers to speculate that we may have been heading into a prolonged period of lower solar output, similar to the Maunder Minimum, a period between 1645 and 1715 when only 50 sunspots were recorded, as opposed to the 40,000 to 50,000 that would typically be seen over a similar 70-year period.

When solar cycle 25 got underway in December 2019, it was also predicted that the cycle would reach its maximum sometime in 2025; however, the Sun had other plans, waking into a very active state at least a year earlier than what was called for, including a series of X-class solar flares that resulted in spectacular aurorae around the globe when their coronal mass ejections reached the Earth’s magnetosphere in early May 2024.

This increased activity appears to mean that we’re well into the solar maximum of solar cycle 25, although we won’t know if the cycle has reached its peak until a decline in the sunspot count has shown a consistent decrease. And although solar cycle 25 appears to mark a return to normal activity levels, it’s important to remember that the most intense geomagnetic storm in recorded history, 1859’s Carrington Event, occurred during an otherwise-average solar cycle, and would be devastating to our modern electrical grid if it were to happen today. Whitley outlines the danger presented by solar storms of that magnitude—and what needs to be done to weather such a storm—in his 2012 ebook Solar Flares: What You Need to Know.