Trip Planning

Statistically, springtime (March/April) and autumn (September/October) contain the most "geomagnetically disturbed days" which means more aurora activity...although you're bound to see the lights in October, November, December, January and February if you spend enough time looking up.

In Yukon, it's dark enough to see the northern lights from about August-through-April. During May, June & July it's just too bright in to see them in the "Land of the Midnight Sun."

To see aurora you need clear and dark sky. During very large auroral events, the aurora may be seen throughout the US and Europe, but these events are rare. During an extreme event in 1958, aurora was reported to be seen from Mexico City. During average activity levels, auroral displays will be overhead at high northern or southern latitudes. Places like Whitehorse, Yukon; Yellowknife, NWT; Gillam, Manitoba; the southern tip of Greenland; Reykjavik, Iceland; Tromsø, Norway; and the northern coast of Siberia all offer a good chance to view the aurora overhead. In North Dakota, Michigan, Quebec, and central Scandinavia, you might be able to see aurora on the northern horizon when activity picks up a little. In the southern hemisphere the aurora has to be fairly active before it can be seen from places other than Antarctica. Hobart, Tasmania, and the southern tip of New Zealand have about the same chance of seeing aurora as Vancouver, BC, South Dakota, Michigan, Scotland, or St. Petersburg. Fairly strong auroral activity is required for aurora viewing in those locations.

The best time to watch for aurora is around midnight, but aurora occurs throughout the night. There are very few places on Earth where one can see aurora during the day.

Since clear sky and darkness are essential to see aurora, the best time is dictated by the weather, and by the sunrise and sunset times. The moon is also very bright, and should be taken into account when deciding on a period to travel for the purpose of auroral observation. You might see aurora from dusk to dawn throughout the night. The chances are higher for the three or four hours around midnight.

Aurora is a luminous glow of the upper atmosphere caused by energetic particles entering the atmosphere from above.
This definition differentiates aurora from other forms of airglow, and from sky brightness that is due to reflected or scattered sunlight. Airglow features that have "internal" energy sources are more common than aurora. For example, lightening and all associated optical emissions like sprites should not be considered aurora.

On Earth, the energetic particles that make aurora come from the geospace environment, the magnetosphere. These energetic particles are mostly electrons, but protons also make aurora. The electrons travel along magnetic field lines. The Earth's magnetic field looks like that of a dipole magnet where the field lines are coming out and going into the Earth near the poles. The auroral electrons are thus guided to the high latitude atmosphere near each pole. As the electrons penetrate into the upper atmosphere, the chance of colliding with an atom or molecule increases the deeper they go. Once a collision takes place, the atom or molecule takes some of the energy of the energetic particle and stores it as internal energy while the electron goes on at a reduced speed. The process of storing energy in a molecule or atom is called "exciting" the atom. An excited atom or molecule can return to the non-excited state (ground state) by sending off or emitting a photon, i.e. by making light.