Dictionary of English - continual, continuous, or constant
continual, continuous, or constant
Something is continual if it happens repeatedly: Our holiday was ruined by the continual rain (it rained often but not all the time). It is continuous if it goes on without a break: Our holiday was ruined by the continuous rain (it rained all the time). If something is constant it happens many times in the same manner: Ruth suffered from constant colds as a child.