The Himalayan area near Tibet are situated on higher latitudes as compared to the Himalayas of Nepal. The temperature decreases with increase in latitudes. Therefore, the snow on the slope of Himalayas in Nepal melts faster than that on the slope towards Tibet.
Tropical deserts are free of cloud cover. This results in their quick heating as well as quick cooling due to radiation of heat. Therefore, tropical deserts have a large annual range of temperatures.
Equatorial region receives maximum insolation and heat throughout the year. The hot air rises up creating low pressure in this area.