The storm petrel is migratory, spending the Northern Hemisphere winter mainly in cool waters off the coasts of South Africa and Namibia, south to latitude 38°S and east to KwaZulu-Natal. Some birds stay north of the equator in the seas adjoining Mauritania and Rio de Oro, and a few remain near the breeding islands, especially in the Mediterranean. It is strictly oceanic outside the breeding season, although it is described as regularly seen from land in West Africa. Young birds do not return to the breeding colonies until their second or third year. Birds mostly head south from the breeding islands between September and November, reaching West Africa by mid-November and the south Atlantic by the end of the year. The return passage starts in April, with late records from the tropics and further south probably representing subadult birds that will not breed that year.