Northern Lights Forecast: Wisconsin Could See Aurora Borealis on September 20–21
GREEN BAY, Wis. — Wisconsinites may be treated to another display of the aurora borealis this weekend, as forecasts suggest the northern lights could be visible across parts of the state on Sept. 20 and 21.
Where the Lights Could Be Seen
According to the NOAA Space Weather Prediction Center (SWPC), the northern portion of Wisconsin is within the viewing line for Sept. 20, with conditions possibly extending visibility as far south as central Wisconsin by Sept. 21.
The forecast shows a Kp index of 3 on Sept. 20 and 4 on Sept. 21, indicating moderate geomagnetic activity. SWPC notes that Kp indexes in the 3–5 range often produce brighter, more active auroras farther from the poles.
Weather Conditions Could Interfere
Clouds and storms may limit visibility in some areas. The National Weather Service predicts a 50% chance of thunderstorms in Green Bay and Appleton on Sept. 20, with scattered showers after. By Sept. 21, storm chances drop to 30% in Green Bay, Appleton, Wausau, and Stevens Point, giving skywatchers better odds for clear skies.
Best Time and Tips for Viewing
Experts say the aurora is most visible between 10 p.m. and 2 a.m., typically peaking within an hour or two of midnight.
Viewers are encouraged to:
- Head away from city lights to darker rural areas
- Look for higher vantage points like hills or towers
- Monitor SWPC’s short-term aurora forecast tools for updates
The timing coincides with the fall equinox on Sept. 22, a period when geomagnetic storms — and auroras — are historically more common.
Top Wisconsin Viewing Spots
Some of the state’s best dark-sky locations include:
- Newport State Park (Ellison Bay)
- Driftless Region (Vernon County)
- Harrington Beach State Park (Belgium)
- Kettle Moraine State Forest (Eagle)
- Kohler-Andrae State Park (Sheboygan)
- Parnell Tower (Plymouth)
With clear skies, Wisconsin residents from the Northwoods to central counties may have a chance to see the aurora borealis this weekend. For more local updates and seasonal highlights, follow ChicagoMusicGuide.com.