Northern Lights Forecast Tonight

How to Read This Forecast

Start with the big percentage. It is the best hourly chance of seeing aurora at the selected place tonight. High (70% or more) means it is worth going out. Moderate (40–69%) means watch the sky and the clouds. Low (15–39%) is a long shot. Unlikely means stay warm.

Next to it you will see Kp needed and Kp now. Kp is a 0–9 scale of geomagnetic activity. The further you are from the Arctic, the higher Kp has to climb before the aurora reaches your sky. When Kp now is at or above Kp needed, the aurora is close enough to see if the sky is clear and dark.

The bars show each hour of tonight’s dark window, from dusk to dawn, in your local time. The number under each bar is the forecast cloud cover. A strong Kp with 90% cloud still means you will not see much, so the hours with the tallest bars and the lowest cloud are your best window.

The three-night strip helps you plan ahead. Kp forecasts are reliable for about one to three days; beyond that we use NOAA’s 27-day outlook, which is a rough guide only.

How the Aurora Chance Is Calculated

The aurora borealis, or northern lights, forms in an oval around the north magnetic pole (the aurora australis does the same around the south). When the Sun sends a fast stream of solar wind or a coronal mass ejection, the oval brightens and expands toward the equator. The Kp index measures that disturbance every three hours.

For each place we convert its geographic position to geomagnetic latitude, which is what matters for aurora. Fairbanks sits near 65.7° geomagnetic and needs only Kp 1. Chicago sits near 50.7° and needs about Kp 8. North America lies closer to the magnetic pole than Europe at the same map latitude, which is why Minnesota sees aurora more often than southern Sweden.

We then compare the expected Kp for each hour with the Kp needed, raise the chance when NOAA’s OVATION model shows aurora overhead in the next half hour, and reduce it for cloud cover, daylight or twilight, and a bright moon. The result is an estimate, not a promise. The aurora can still appear on a low night or stay away on a high one.

Example: Rovaniemi needs Kp 2. With Kp 4 forecast, 10% cloud, and full darkness, the chance is high. The same Kp with 90% cloud drops to almost nothing.

Northern Lights Viewing Tips

Get away from streetlights. Even a short drive to a dark field or lakeshore makes faint aurora visible. Face north (south in the southern hemisphere) and give your eyes 15–20 minutes to adapt to the dark. Use red night mode on this site to protect your night vision.

Watch the clouds, not just Kp. Check the hourly cloud row and look for gaps. Coastal and mountain weather can change fast, so a cloudy forecast at 20:00 can clear by midnight.

Your phone camera sees more than your eyes. On a modern phone, night mode with a 3–10 second exposure often shows green or pink aurora that looks like grey haze to the eye.

Activity often peaks within an hour or two of local midnight, but strong storms can light up the sky as soon as it gets dark. Set a free aurora alert so you do not have to keep checking.

Aurora Forecast Tonight by Region

Where you are decides how strong the aurora has to be. In Alaska, Yukon, the Northwest Territories, Iceland, and northern Norway, Sweden and Finland, the aurora borealis is overhead on most clear, dark nights, so the cloud forecast matters most. In southern Canada, Scotland and the northern US states from Washington to Maine, you usually need Kp 4 to 6. London, Chicago, Oregon and Colorado need a strong storm of Kp 7 or more.

See every place we forecast ranked by tonight’s chance on where to see the northern lights tonight, watch the live oval on the aurora map, and check the exact Kp each place needs on the Kp index page.