Northern lights in Portland tonight
Maine, USA · 51° magnetic latitude · Kp 6 threshold
Kp 1 is well below the Kp 6 threshold needed for aurora to be visible from Portland.
7-day outlook for Portland
Based on CME arrival predictions from NASA DONKI. Arrival times ±6 hours.
auroratonight.space
What Kp is needed here?
Portland sits at a magnetic latitude of approximately 51°N. The Kp index - a global measure of geomagnetic activity on a scale from 0 (quiet) to 9 (extreme storm), updated every 3 hours - needs to reach Kp 6 before the auroral oval expands far enough south to be visible from here.
At Kp 6, visibility is possible from Portland but skies need to be clear and dark. Cloud cover and light pollution remain the main obstacles even when Kp is high enough.
Best dark sky sites near Portland
Light pollution is the biggest obstacle after cloud cover. These sites give you the best dark northern horizon within reach.
Cape Elizabeth - Fort Williams Park
Get directions ↗Rocky Atlantic coastline 6 miles south of Portland. Fort Williams Park surrounds Portland Head Light and opens onto a north-facing shore with the ocean horizon extending to the northeast. Light pollution from Portland is behind you when facing north, and the lighthouse makes a strong foreground for photography. Open year-round and free.
Two Lights State Park
Get directions ↗Cape Elizabeth, adjacent to Fort Williams Park. The rocky headland faces north and northeast over the open Atlantic with minimal development nearby. Parking is available at the trail access points, and the exposed shoreline drops most of the ambient glow from Portland. Bortle 4-5 conditions on the coast itself, improving to Bortle 3-4 on the ocean-facing rocks away from the parking area.
Acadia National Park - Cadillac Mountain
Get directions ↗Three hours north on Mount Desert Island. At 466 meters, Cadillac Mountain is the highest point on the US East Coast north of Rio de Janeiro, and the summit is accessible by car via the Summit Road from May through November. Acadia carries an International Dark Sky designation, and the summit's 360-degree horizon above the tree line makes it one of the most capable aurora-viewing positions in the northeast. On nights when Portland is marginal, Cadillac is often unambiguously clear.
Best time to see the northern lights in Portland
At 51°N magnetic latitude, Portland sits at the lower end of regular aurora territory. Only the deep mid-winter months of November through January offer nights dark enough for aurora to be visible, and only then when a significant geomagnetic storm pushes the auroral oval this far south.
Activity peaks around the September and March equinoxes, when Earth's magnetic field geometry is most favourable for coupling with the solar wind. Events during these two windows tend to produce the strongest displays of the year for observers at Portland's latitude.
Outside November through January, twilight is too bright for aurora viewing even during significant storms. The season is short, but the equinox months on either side of winter can extend it slightly when storm timing aligns.
Up to 8 locations
How often does the aurora appear in Portland?
Average nights per month the Kp reached Portland's threshold of 6+, from 15 years of geomagnetic data (2010–2024).
Counts the Kp 6+ threshold only - cloud cover and local darkness are not included.
Kp data: GFZ German Research Centre for Geosciences, CC BY 4.0
Plan your trip to Portland
Best window
The January to March window averages 1 aurora nights - the strongest consecutive stretch of the year.
How long to stay
Aurora at this latitude requires patience - allow as many nights as possible during March.
Related pages
Northern Lights USA
USA-wide aurora forecast hub.
Read →Northern Lights Burlington Tonight
Burlington - Lake Champlain north-facing horizon.
Read →Northern Lights Maine
Maine statewide aurora forecast, from Portland to Acadia and the north woods.
Read →Northern Lights New Hampshire
New Hampshire aurora forecast and White Mountains dark sky guide.
Read →What Is the Kp Index?
What Kp 6 means for aurora viewing at 51° geomagnetic latitude.
Read →Aurora photographs from Portland
Real photos sourced from Wikimedia Commons.
Aurora over Portland 
Aurora over Portland 
Aurora over Portland 
Aurora over Portland 
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