Issue 69
October 13, 2006

Weather Trivia

 You Asked Us

Environment Canada's knowledgeable specialists answer questions about wildlife, air pollution, water, weather, climate change and other aspects of the environment.

  Print Version            E-mail this page            More Questions

Does the weather affect the Northern Lights? Where and when is it best to view them?

As Canadians, we are fortunate to live in the country with possibly the best view of the Aurora Borealis, or Northern Lights.

The Aurora Borealis is not a weather related phenomenon; it occurs many miles up, in the upper atmosphere – weather exists below this region. Although there is not a direct link between the Northern Lights and weather, there are a few weather-related points which may contribute to the quality of viewing this extraordinary phenomenon:

• It is possible that the view of the Aurora Borealis might be affected by a high pressure system, simply because the skies will tend to be clearer and cloud cover would not be blocking the view of the sky.
• The Aurora Borealis occurs year-round, yet seems to appear more frequently in winter. This may simply be because nights are longer in winter.
• The Aurora is present during the day, but we just don't see it as often. Technically, it can be observed in the daytime, but only on dark days, such as in the Arctic during mid-winter, when the sun does not rise.

In Canada, the Northern Lights can be seen anywhere there is an open view of the sky, but as a general guideline, the farther north you go, the more spectacular the display will be. Northern Canada's lower levels of light pollution and proximity to the North Pole contribute to a superior view of the lights.

The Aurora is a result of the interaction between the solar wind and Earth's magnetic field. The solar wind is a hot stream of plasma (made of negative electrons and positive protons) emanating from the sun into the galaxy. When the solar wind reaches the upper atmosphere, the Earth's magnetic field attracts the plasma particles and directs them to the northern or southern poles, producing a reaction that results in the spectacular display of colours.

The colours of the Aurora are either a combination of red and green light, or of red and blue light. Nitrogen in the atmosphere makes the aurora red and blue, while oxygen causes the red and green colours to appear.

The Aurora Borealis appears as an oval that covers the North Pole. (The Aurora Australis covers the South Pole). The size and shape of these ovals change depending on the speed of the solar wind. When activity on the sun is reduced and the solar wind is calm, the oval is small and thin.

When the sun is more active, it sends more particles towards the Earth. The magnetic field attracts all those particles to the north and south poles making the oval wider, stretching it towards the equator. When this occurs, chances of a better view of the Northern Lights in southern Canada and the United States are increased.

Related Links:

• Canadian Space Agency – Aurora Borealis
• Hourly Auroral Activity Report
• Aurora Forecast for Your Region
• Probing the secret life of the Auroras
• THEMIS: the stakeout for northern lights in the Canadian tundra
• Auroras – What makes them happen?