Wind is most often from the south from mid-March to the end of August. During this weather pattern the wind and sea conditions get rougher after 2pm. This means it is harder to spot the dolphins when the waves are kicking up, especially if the dolphins just breach their top fin out of the water.
The wind then shifts to the north from the end of September 25 to mid-March. Starting in October, the dolphins who live off of the Virginia and North Carolina coasts start to head south. Therefore, your chances of seeing dolphins in the October to November time frame can be pretty good. In fact, November and December are peak migration months for these dolphins, but with the shorter days, people may feel they see less dolphins in December.
Not all dolphins leave for the winter, so you can see a dolphin off the North Myrtle Beach shore year around. In fact, the dolphins who winter out off the shore are the same type as those who choose to migrate. Then in March, those who wintered further south will make their way back north again, making March and April good months to catch a glimpse of these intelligent and sleek animals, in the morning.