At 2:19 p.m. EDT on Monday, September 22, 2025, the sun will officially cross the celestial equator, marking the fall equinox in the Northern Hemisphere. While this shift signals the start of autumn with shorter days and longer nights, it also sets the stage for something even more spectacular: enhanced chances of seeing the Northern Lights.

 

Why the Equinox Matters for Auroras

 

The aurora borealis, or Northern Lights, happens when charged particles from the sun travel along Earth’s magnetic field lines and collide with gases high in the atmosphere. These collisions release energy as shimmering green, red, and sometimes purple lights across the night sky.

 

Although the sun’s magnetic activity is the root cause of auroras, scientists have noticed a boost in geomagnetic disturbances around the equinoxes in March and September. This phenomenon, called the “equinox effect,” is all about geometry. At equinox, Earth’s axis tilts side-on to the sun, aligning the planet’s magnetic poles in a way that makes it easier for solar wind particles to slip into Earth’s magnetosphere. The result: a higher chance of auroras.

 

Forecast for September 21

 

NOAA’s Space Weather Prediction Center has forecast a G1-rated geomagnetic storm for Sunday, September 21. A G1 storm is classified as minor, but it can still expand the aurora’s reach further south than usual. According to NOAA’s experimental aurora viewline, the Northern Lights could be visible across 14 U.S. states, making this an exciting opportunity for sky-watchers far from the Arctic Circle.

 

When and Where to Look

 

While the equinox itself occurs on September 22, the aurora forecast is for the night of Sunday, September 21 into the early hours of Monday, September 22. For the best chances to see the auroras:

 

Head out after nightfall on September 21.

 

Find a dark spot away from city lights.

 

Look toward the northern horizon.

 

 

Remember, actual visibility will depend on local weather conditions, solar activity, and how strong the storm truly becomes. Even with forecasts, auroras can be unpredictable—but that’s part of their magic.

 

Why This Year Is Special

 

This equinox comes as the sun approaches the peak of its 11-year solar cycle, a time when solar storms are more frequent and more powerful. That means stronger auroras are likely in the months ahead. The weeks before and after the equinox are particularly favorable, so sky-watchers should keep checking NOAA’s forecasts and aurora viewline maps.

The fall equinox is already a special astronomical milestone, but this year it comes with the promise of glowing skies. With