A region in which the amount and seasonal variation of rainfall are of a given type. According to Köppen in his climatic classification, the main types of hyetal regions are 1) desert, with rainfall rare and irregular; 2) winter-dry, with main rainy season in summer, characteristic of a monsoon climate; 3) summer-dry, with rainy season in winter, such as a Mediterranean climate; 4) rain at all seasons, but not evenly distributed through the year; 5) rain on more than half the days in every month of the year. Minor types may be distinguished in which the season of rainfall maximum is either broken by a short dry season or is displaced toward spring or autumn. Compare humidity province.