Where are we in the solar cycle?

The Sun is a star: a ball of hot gas held together by its own gravity and lit by fusion in its core. The gas is electrically charged, and its churning makes the Sun's magnetic field. That field is never still.

Where the field pushes up through the surface, we see sunspots: dark patches, a little cooler than the gas around them. The number of spots rises and falls in a rhythm that lasts about 11 years on average, though single cycles run shorter or longer. At solar minimum there are few spots or none. At solar maximum the Sun is crowded with them, and flares and eruptions are common.

Each cycle also turns the Sun's magnetism upside down. Once in every cycle, its north and south magnetic poles swap places. So the full magnetic rhythm, back to where it began, takes two cycles.

Cycles are numbered from Cycle 1, which began in 1755. The cycle we live in now, Solar Cycle 25, began in December 2019, when the smoothed sunspot number reached its low.

It climbed faster and higher than expected. In 2019 a panel of NOAA, NASA and international experts had forecast a smaller peak, in July 2025. The smoothed number peaked in October 2024 at 160.9, about 1.4 times the peak of the cycle before. Near the top, on 10 May 2024, an extreme geomagnetic storm brought the aurora far from the poles.

The latest monthly sunspot number is 60.3. Monthly numbers jump about, so the cycle is judged by a 13-month average instead. That smoothed number is now 94.4, and it always runs some months behind, because it needs months of data on either side.

We are on the long slope down from the peak. NOAA updates its forecast for the rest of Cycle 25 every month, from the numbers observed so far. It does not yet forecast Cycle 26, but it expects the new cycle to begin some time between January 2029 and December 2032.

A new cycle shows itself in a particular way. Its first sunspots appear far from the Sun's equator, with their magnetic poles the other way round from the old cycle's spots.

Because the smoothed number needs months of data on either side, the start of Cycle 26 will be named only well after it has happened. And a quieter Sun is not a sleeping one. Flares and storms grow rarer, but they do not stop.

People have watched sunspots through telescopes since the early 1600s. Monthly counts go back to 1749, and today the Royal Observatory of Belgium keeps the record. No two cycles in it are alike. The strongest, Cycle 19, peaked in March 1958 at a smoothed number of 285.0. Cycle 24, which ended in 2019, peaked at only 116.4, the weakest since the early 1900s.

The record also holds a puzzle. From about 1645 to 1715, sunspots almost vanished. Astronomers were watching, so the gap is real, not a hole in the notes. This quiet spell is called the Maunder minimum.

It came during a cold period called the Little Ice Age, when rivers that are normally free of ice froze over. How much the quiet Sun had to do with that is still being studied.

Near maximum, the Sun throws out more flares and more coronal mass ejections, vast clouds of charged gas. When one reaches Earth, it can shake the magnetic field we live inside. That shaking is a geomagnetic storm. NOAA expects about 1,700 minor storms in an average cycle, and about 4 extreme ones.

Storms bring the aurora far from the poles. They can also strain power grids and disturb satellites and GPS. Strong flares, more common near maximum, can black out shortwave radio on the daylit side of Earth. The latest storm reading is “No storm”.

The cycle even changes how long satellites last. Near maximum, the drag on satellites in low orbit grows, so they come down sooner. That is one reason satellite operators watch NOAA's forecast.