The Northern Lights a spectacular display of dancing colorful light in the sky, can be seen in Iceland from late September until beginning of March. The magnitude of the lights is based on solar winds which affects the magnetosphere and the visibility is affected by cloud cover, as the Aurora Borealis are formed way above the clouds.

The photo above is by Moyan Brenn at http://flickr.com/photos/28145073@N08/9997912316. and is licensed under the terms of the cc-by-2.0.