(a) Bikaner lies on the edge of the Thar Desert. The land has little vegetation cover so it absorbs heat quickly in the day and loses it quickly in the night. For this reason, it is very hot during the day and quite cold during the night. Hence, Bikaner is said to have a high diurnal range of temperature.
(b) The Aravallis are parallel to the direction of the Arabia Sea branch of the South West Monsoon. Hence there is no rainfall in Rajasthan due to this branch. On the other hand, the Aravallis block the Bay of Bengal branch towards their east which is why there is little or no rainfall in the western part of Rajasthan where the Thar Desert lies.
