Back in May, the Northern Lights lit up the skies as far south as Florida, treating much of the country (except New York City) to the rare colorful, illuminated display. If you missed your chance to see the aurora, or want to see it again, you may have another chance this weekend.

The National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC) has issued a watch for geomagnetic storms—the kind that may result in displays of the Northern Lights—for Friday, Oct. 4 through Sunday, Oct. 6.

What do geomagnetic storms have to do with the Northern Lights?

This all started with two strong solar flares (eruptions on the sun), on Oct. 1 and 3—the latter of which was the most powerful since 2017. Each solar flare was accompanied by a coronal mass ejection, which is an explosion of plasma and magnetic fields from the sun’s corona that can cause geomagnetic storms when they’re directed at Earth. This has prompted the SWPC to issue a G3 (Strong) geomagnetic storm watch for Oct. 4 through 6.

NOAA uses a G-scale to measure the intensity of geomagnetic storms, ranging from G1 for minor storms to G5 for the most extreme storms. The higher the number, the more of a chance there will be to see the aurora. Stronger geomagnetic storms also carry the risk of potential infrastructure disruptions, including to the electric power grid, communications, navigation, radio, and satellite operations, though the SWPC has indicated that the arriving storms should only result in “limited, minor effects to some technological infrastructure” which will be “mainly mitigatable.”

How and where to see the Northern Lights

If the SWPC’s predictions are correct, and this weekend’s geomagnetic storms result in G3 conditions, the Northern Lights may be visible “over many of the northern states and some of the lower Midwest to Oregon.” But even if the storm doesn’t end up being that strong, or you live south of where the aurora can be seen with the naked eye, you may be able to use your phone to catch a glimpse of the northern lights.

The best time to see the aurora is usually between 10pm and 2am. While it may be possible to see it in the evening or early morning, “it is usually not as active and therefore, not as visually appealing,” the SWPC notes.

As usual, for the best chances of seeing any celestial activity, head to the darkest skies near you. But first check the weather forecast: Any type of precipitation or cloud cover could block your view of the colorful display. And while you’re at it, keep an eye on the SWPC website and their aurora dashboard for the most up-to-date aurora information.