If you are a whale fanatic or just like to see those massive mammals up close then Grundarfjörður is the place to be from november until march. You can go on a boat ride from Grundarfjörður harbour or sometimes even just see the whales from the harbour as they often come really close to shore.
This picture was taken on 20. february 2011.
As for the boat ride you can contact Láki Tours for information. There is almost a guarantee that you will not be disappointed as there is a whale sighting almost every time.
If you are off season then there is always alot to see besides whales as the fjord is rich with birdlife and often it is possible to try your fishing skills.
All the pictures are from my flickr webpage