Space Weather by the Seasons express

Original: "Analysis of Short-term Solar Activity Variability and Estimating the Timings of the Next Enhanced Bursts"
· Juie Shetye, Mausumi Dikpati
arXiv:2605.27057 · 2026-05-26 · CC BY 4.0 · 2 min
The Sun doesn't just simmer randomly: it flares in short bursts that can be predicted six months ahead.

The Sun doesn't burn steadily: it erupts in series. Like a campfire that dies down and then suddenly throws out showers of sparks, these "fiery seasons" last from six months to a year and a half, and during them the star shows an unusually high number of sunspots. A team of researchers took sunspot data going back to 1878 and taught a computer to recognize when the next fiery outburst is approaching.

Instead of looking at the Sun as a whole, they split it into north and south. Each hemisphere follows its own rhythm: the north peaked at about 70 spots in March 2025, while the south went wilder — up to 130 spots at nearly the same time. The difference was captured using a mathematical model similar to predicting seasonal sales in a store: it accounts for both smooth trends and sharp jumps.

Sunspots are regions where the magnetic field bursts through and slightly cools the surface. That's why they look dark, even though they're still scorching at 4000 degrees.

Then came the "forest predictor"—the random forest algorithm, which learns from examples. It was fed hundreds of past surges and learned to guess how strong the next one would be. This hybrid of statistics and machine learning already correctly pointed to the rise in activity in late 2024 and early 2025. The next flare-up is expected in December 2025, with the southern hemisphere again setting the tone. The overall strength of the storms depends mostly on it.

The Sun's magnetic field flips every 11 years. But within that cycle hide shorter "seasons," which the authors of the study have now predicted.

A sunspot the size of a small city can trigger a magnetic storm on Earth that knocks out navigation systems.

Scientists
Ludwig BoltzmannEnrico FermiCecilia Payne-GaposchkinJoseph von FraunhoferFred Lawrence WhippleGalileo Galilei
Concepts
solar flare prediction solar cycle forecasting quasi biennial oscillation monsoon onset forecast sunspot Westerly wind burst Forecast lead El Niño-Southern Oscillation seasonal cycle interannual variability seasonal forcing OISST NRT spring predictability barrier space weather ensemble forecast Multivariate ENSO Index