Northern Lights May Be Visible in the Lower 48 Tonight

This spring, the Northern Lights graced the Lower 48, illuminating the night sky with colorful streams as far south as New Mexico. If you missed it, don't worry—tonight offers another opportunity to witness the elusive aurora borealis in the Lower 48.

Researchers at the University of Alaska Fairbanks Geophysical Institute assess the likelihood of seeing the aurora borealis using the Kp Index, which ranges from zero to nine. A higher index indicates a greater chance of witnessing this nighttime phenomenon across a wider area of the hemisphere.

For the night of September 18 and the early morning of September 19, the Kp Index is at six. This suggests the Northern Lights may be visible as far south as Oregon, Idaho, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, and throughout the Northeastern states. However, it's more likely that if the display occurs in the continental U.S., it will be seen in the northern regions of Washington, Montana, the Dakotas, Minnesota, Wisconsin, Michigan, and Maine.

What triggers the Northern Lights—and when can we expect to see them again?

The aurora borealis occurs when the sun emits electrically charged protons and electrons towards Earth during a solar storm. When these particles collide with the Earth’s magnetic field, they are drawn to the poles, where they interact with gases in the atmosphere. This interaction creates green and red lights when mixed with oxygen, and blue and purple hues when combined with nitrogen. It’s a similar process to what happens in neon signs.

Even if you miss this spectacular display, your chances of witnessing it will only increase in the coming years. An 11-year cycle has historically indicated when the lights are most likely to be seen. During the years approaching solar maximum (expected in 2024), the displays become more frequent, vibrant, and energetic (while they tend to be less dynamic near solar minimum). Expect more frequent and vivid shows in the coming years, especially around the fall and spring equinoxes.

Advice for viewing the Northern Lights

Consider downloading a mobile app like Northern Light Aurora Forecast to assess the chances of witnessing the Northern Lights in your location. It can indicate when the spectacle might occur, if at all.

Keep in mind that the Northern Lights can only be seen with a clear sky, away from the interference of city lights. For the best experience, seek a location, such as the top of a hill, that offers unobstructed views of the northern sky.

If conditions are favorable and you’ve secured a good vantage point, be patient. Just as it's impossible to pinpoint the exact moment it will start snowing, there's no definitive way to know precisely when the aurora borealis will emerge or how long it will last.

This article was initially published in 2022 and was most recently updated on September 18, 2023, with new information.