How the northern lights are created? There are two answers: #1 says that they are formed when charged particles emitted from the sun during a solar flare penetrate the earths magnetic shield and collide with atoms and molecules in our atmosphere. #2 Is my own theory, and I guess the picture speaks by itself. Which one make more sense for you? #TravelTip: The northern lights in Iceland can be spot from September to mid April, always depending of course on your luck with the weather.