Whale migration occurs twice in a year, once when the whales travel north to give birth to their young ones and the other time when the whales travel back south with their offspring to food-rich seas.
Winter migration: During the winter, usually from April to August, pregnant whales travel north. This migration usually peaks in June and July.
Spring migration: Once mama whales have given birth to their young ones, they migrate back south to Antarctica. This movement starts in mid-August and goes on till November. The spring migration is actually more spectacular as mother whales are tending to their young ones, teaching them to breach and hunt for food. Young males are usually quite eager to jump out of the waters at this time as well! So, if you're unable to go whale watching in the winter, you can come between August and November instead for an incredible display.
The best time to spot whales in a day is usually between 11am and 3pm when the sun is right on top granting spectacular visibility.