In physical geography, a steppe (Ukrainian: степ Russian: степь, tr. step'; IPA: [sʲtʲepʲ] ( listen)) is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas, and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes. The prairie (especially the shortgrass and mixed prairie) is an example of a steppe, though it is not usually called such. It may be semi-desert, or covered with grass or shrubs or both, depending on the season and latitude. The term is also used to denote the climate encountered in regions too dry to support a forest, but not dry enough to be a desert. The soil is typically of chernozem type.Steppes are usually characterized by a semi-arid and continental climate. Extremes can be recorded in the summer of up to 40°C (104°F) and in winter, –40°C (–40°F). Besides this huge difference between summer and winter, the differences between day and night are also very great. In the highlands of Mongolia, 30°C (86°F) can be reached during the day with sub-zero °C (sub 32°F) readings at night.The mid-latitude steppes can be summarised by hot summers and cold winters, averaging 250–500 mm (10-20 inches) of precipitation per year. Precipitation level alone is not what defines a steppe climate; potential evapotranspiration must also be taken into account.