The northern lights could push into a dozen states as the Sun nears its stormy peak

The northern lights are usually thought of as a spectacle reserved for the far north, visible from places like Alaska, northern Canada, and Scandinavia. But during the most active stretch of the Sun’s activity cycle, the glowing curtains of the aurora can be pushed much farther south than usual, occasionally becoming visible across a dozen or more of the lower 48 states. With the Sun currently in the stormy phase of its 11-year cycle, sightings well beyond the usual latitudes have become notably more common.

The aurora is driven by the Sun, not by anything happening on Earth, which is why its intensity rises and falls in step with solar activity. As that activity climbs, so do the odds that a burst of energy from the Sun will slam into Earth’s magnetic field hard enough to light up skies far from the poles. Forecasters track these conditions closely, and their predictions determine how far south a given display is likely to reach.

What creates the aurora in the first place

The northern lights, formally called the aurora borealis, are produced when charged particles streaming from the Sun collide with gases high in Earth’s atmosphere. When those particles are funneled along Earth’s magnetic field lines into the upper atmosphere, they excite oxygen and nitrogen atoms, which then release the energy as light. Oxygen tends to glow green and red, while nitrogen can add blues and purples, producing the shifting colors that define an auroral display.

Ordinarily this activity is concentrated in a ring around the magnetic pole, so the lights stay near the Arctic. During strong disturbances, though, that ring expands and the auroral glow slides toward the equator. The measure forecasters use to gauge how far it will reach is the Kp index, a scale from 0 to 9 that describes the level of geomagnetic activity. The higher the Kp value, the farther south the aurora can be seen, and it is the tool the NOAA Space Weather Prediction Center highlights for aurora watchers.

Why solar storms send the lights south

The events that supercharge the aurora originate in the Sun’s turbulent outer layers. Solar flares and, more importantly, coronal mass ejections, enormous eruptions of solar plasma and magnetic field, can hurl billions of tons of charged material toward Earth. When one of these clouds reaches the planet a day or several days later and connects with Earth’s magnetic field, it can trigger a geomagnetic storm that dramatically intensifies and expands the aurora.

The strength of that storm determines the reach of the lights. A modest disturbance might extend the aurora into the northern tier of states, while a severe geomagnetic storm can carry visible displays into the middle of the country and, in exceptional cases, much farther. Because coronal mass ejections take time to travel from the Sun to Earth, forecasters can often issue watches a day or more in advance, giving sky watchers a window to plan around clear, dark conditions away from city lights.

Where the Sun is in its cycle now

The Sun runs through a roughly 11-year cycle in which its activity climbs to a maximum and then subsides. The current cycle, designated Solar Cycle 25, reached the peak of its sunspot count in late 2024, and activity has remained elevated since then. That places the present period squarely within the active, storm-prone stretch that scientists track through NASA and NOAA’s monitoring of the solar cycle.

Importantly for aurora watchers, the strongest geomagnetic storms and the most widespread auroras do not always coincide exactly with the peak in sunspots. The large eruptions that fling material toward Earth often remain frequent in the years immediately following the sunspot maximum, during the cycle’s declining phase, so the stormiest conditions for auroras can persist through this period. That is why displays reaching unusually far south have continued to occur, and why forecasters expect further opportunities while the Sun stays active.

How to catch a display when the forecast lines up

Seeing the aurora from the lower states depends on more than solar activity. A viewer needs a clear night, a location well away from urban light pollution, and an unobstructed view toward the northern horizon, since from southern latitudes the lights often appear low in the sky rather than directly overhead. The hours around midnight tend to offer the best chances during an active period, and the darker skies of a new moon help faint displays stand out.

Real-time and short-term forecasts help enormously, because geomagnetic conditions can change within hours. NOAA publishes an aurora forecast that estimates where the lights are likely to be visible in the near term, allowing people to check current conditions before heading out. Combining that short-range guidance with a dark-sky location gives the best odds of catching a display when a storm arrives.

For now, the combination of an active Sun and frequent geomagnetic storms means the northern lights are within reach of far more of the country than in a typical year. As long as the current cycle keeps the Sun in its storm-prone phase, brief chances to see the aurora from states that rarely witness it are likely to keep recurring.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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