During the coastal upwelling in 1974 the ocean temperature along the coast of Ghana exhibited periodic variations at a frequency of 0.07 epd which propagated westward along the coast. Equatorial, shelf and Kelvin waves are discussed and it is found that the wave could be described in terms of any of these types of waves. However in the light of current theories of energy exchange in coastal waves the oscillation is most likely to be an internal Kelvin wave.