Canada · Northern lights
Most people link the northern lights with polar nights far to the north. But when Earth's magnetic field is properly shaken, the ring of aurora moves out over far more populated places. That is exactly what is expected on the night into Wednesday 14 October, around 19:30, when the Kp index may reach 5, according to NOAA SWPC.
| City | Chance | Clouds tonight |
|---|---|---|
| Yellowknife | Good | Partly cloudy |
| Edmonton | Possible | Overcast |
| Winnipeg | Possible | Overcast |
| Toronto | Low | Partly cloudy |
| Vancouver | Low | Overcast |
| Montreal | Low | Overcast |
| Halifax | Low | Overcast |
Where can it be seen?
The best chances are in Yellowknife. There, the northern lights may climb high enough to be seen with the naked eye if the sky is dark and clear.
In Edmonton and Winnipeg, it may appear as a greenish glow or red pillars low in the sky towards the north.
Kp is a global three-hour average. The northern lights come in waves, and an outburst can last ten minutes or two hours, so patience pays off.
Tonight's clouds
Toronto and Yellowknife look set for partly cloudy skies – a few gaps in the cloud can be enough. Thick cloud is expected over Edmonton, Winnipeg, Vancouver, Montreal and Halifax for most of the night, so the chances there are slim. Cloud cover is Skycastor's forecast for the dark hours. It is updated continuously, so check again closer to the time.
How to get the best view
Find a dark spot with an open view to the north. Street lights and the glow of towns swallow the faint colours, and just twenty minutes out of town makes a big difference.
It is dark enough from about 19:39 until 06:28.
Good dark places include Jasper, Wood Buffalo, Mont-Mégantic and Kejimkujik.
Give your eyes 15–20 minutes to adjust to the dark, and avoid looking at your phone screen in the meantime.
Try your phone's night mode, or a camera on a tripod with a 5–15 second exposure. The picture often shows stronger colours than the eye can see.
What is happening on the Sun?
Auroras form when electrically charged particles from the Sun hit Earth's magnetic field and are channelled down into the atmosphere around the poles. At 100–300 kilometres up, they collide with oxygen and nitrogen, which light up – oxygen in green and red, nitrogen in blue and violet.
That corresponds to a minor geomagnetic storm, G1 on NOAA's scale from 1 to 5.
The Kp index runs from 0 to 9 and shows how disturbed Earth's magnetic field is. At Kp 3, the northern lights are usually seen only in northern Norway, Lapland and Iceland. From Kp 5 they can reach Denmark, Scotland and northern Germany, and at Kp 8–9 they have been seen as far south as southern Europe.
Happy hunting – and dress warmly. A clear night turns cold quickly, even after a mild day.