Northern Lights
The Northern Lights, or the aurora Borealis, are caused by eruptions on the sun and can only be seen when it is dark. This means that cruises in May - July, when it is light almost all day, have little chance of seeing the Aurora, but in September and October, and even into November, you can witness the amazing natural phenomenon.
Aurora Borealis Forecast
Remarkably the US Space Weather Prediction Centre has created an Aurora Borealis prediction system, where you can a 3 day prediction of your chances to see the Northern (or Southern) Lights, the Aurora Borealis or Aurora Australis - To find out more about your chances of seeing the northern lights, click Aurora Borealis prediction.