monsoon accounts for most precipitation. Daily summer temperature maxima rise to around ; this results in natural vegetation typically comprising short, coarse grasses. Subtropical humid Most of Northeast India and much of North India are subject to a humid subtropical climate and a subtropical highland climate. Though they experience warm to hot summers, temperatures during the coldest months generally fall as low as . Due to ample monsoon rains, India has two subtropical climate subtypes under the Köppen system: Cwa and Cwb. In most of this region, there is very little precipitation during the winter, owing to powerful anticyclonic and katabatic (downward-flowing) winds from Central Asia. Humid subtropical regions are subject to pronounced dry winters. Winter rainfall—and occasionally snowfall—is associated with large storm systems such as "Nor'westers" and "Western disturbances"; the latter are steered by westerlies towards the Himalayas. Most summer rainfall occurs during powerful thunderstorms associated with the southwest summer monsoon; occasional tropical cyclones also contribute. Annual rainfall ranges from less than in the west to over in parts of the northeast. As most of this region is far from the ocean, the wide temperature swings more characteristic of a continental climate predominate; the swings are wider than in those in tropical wet regions, ranging from in north-central India to in the east. Mountain India's northernmost areas are subject to a montane, or alpine, climate. In the Himalayas, the rate at which an air mass's temperature falls per kilometre (3,281 ft) of altitude gained (the dry adiabatic lapse rate) is 9.8 °C/km. In terms of environmental lapse rate, ambient temperatures fall by for every rise in altitude. Thus, climates ranging from nearly tropical in the foothills to tundra above the snow line can coexist within several hundred metres of each other. Sharp temperature contrasts between sunny and shady slopes, high diurnal temperature variability, temperature inversions, and altitude-dependent variability in rainfall are also common. The northern side of the western Himalayas, also known as the trans-Himalayan belt, has a cold desert climate. It is a region of barren, arid, frigid and wind-blown wastelands. Areas south of the Himalayas are largely protected from cold winter winds coming in from the Asian interior. The leeward side (northern face) of the mountains receives less rain. The southern slopes of the western Himalayas, well-exposed to the monsoon, get heavy rainfall. Areas situated at elevations of 1,070–2,290 metres (3,510–7,510 ft) receive the heaviest rainfall, which