NOAA’s Space Weather Prediction Center (SWPC) issued a revised prediction for solar activity during Solar Cycle 25 that concludes solar activity will increase more quickly and peak at a higher level than that predicted by an expert panel in December 2019. The updated prediction now calls for Solar Cycle 25 to peak between January and October of 2024, with a maximum sunspot number between 137 and 173.
The prediction marks the debut of SWPC’s experimental Updated Solar Cycle Prediction Product on the Space Weather Prediction Testbed website. The website offers SWPC partners and customers the opportunity to provide feedback on the product before it is fully integrated into SWPC operations. During this time, the product will be updated monthly to provide an accurate, up-to-date prediction for the progression of Solar Cycle 25, which began in 2019.
Mark Miesch, a CIRES scientist who serves as the solar cycle lead at SWPC, said the forecast for Cycle 25 had not been updated since its release in 2019 and is no longer reliable enough for SWPC’s customers, many of whom plan their operations years in advance.
“We expect that our new experimental forecast will be much more accurate than the 2019 panel prediction and, unlike previous solar cycle predictions, it will be continuously updated on a monthly basis as new sunspot observations become available,” Miesch said. “It’s a pretty significant change.”
No two solar cycles are the same, Miesch added. Solar magnetic variability - here measured by sunspot number - regulates the frequency and severity of space weather events and hazards, which can interfere with the electrical grid, degrade GPS signals, increase orbital drag on satellites, and pose radiation hazards to airline crews and astronauts. Stronger solar cycles produce more solar storms with greater intensity and therefore pose a larger hazard for these critical technologies and services.
The 2019 panel, convened by NOAA, NASA, and the International Space Environment Services (ISES), predicted that Solar Cycle 25, following a relatively weak Solar Cycle 24, would also be weak, peaking in July 2025 at a maximum sunspot number of 115. Solar Cycle 24 was the weakest cycle in 100 years with sunspot number peaking at 116 for the solar cycle, well below average, which is 179. NOAA’s new prediction, though larger than the panel prediction and larger than Cycle 24, would still make the strength of Solar Cycle 25 below average.