The climate in India varies greatly according to latitude, altitude and season. Similarly, the climate of Rajasthan also varies due to its topography. Rajasthan is one of the driest region in India. Due to its location in the north western part of India, it is more prone to various climatic changes. There are also clear evidences of the advance and retreat of the desert over the last 5000 years from the presence of the fossil sand dunes reaching almost as far as Delhi. The western part of Rajasthan is relatively dry and infertile and mainly consists of the Great Indian Thar Desert. Whereas, the southwestern part of Rajasthan is wet, hilly and fertile.
The climate of Rajasthan varies greatly throughout the state. It is very hot and dry in summer in the desert areas, where dust storms also occur, while it is very cold during the winters. To the west of the Aravali range, the weather is characterized by low rainfall with erratic distribution, extremes of diurnal and annual temperatures, low humidity and high wind velocity. While in the east of the Aravali range, the weather is characterized by relatively low wind velocity and high humidity with better rainfall. The climate of Rajasthan can be divided into four seasons namely Summers, Monsoon, Post Monsoon and Winter.
The summer season is the hottest season and extends from April to June. In summers, the temperature is very high, ranging from 32 degree Celsius to 46 degree Celsius and an average temperature of 38 degree Celsius. During this season, Rajasthan’s only hill station, Mt Abu. registers the lowest temperatures. During the day time the winds blow from the west and sometimes carry dust storms. These winds are known as ‘Loo’. In summers, you should wear light cotton clothes.
The Monsoon season extends from July to September. During this season the temperature drops, but humidity increases. The temperature ranges from 35 degree Celsius to 40 degree Celsius. 90% of rains occur during this period.
The winter season extends from December to March. There is slight precipitation in the north and north eastern region of the state and light winds blow from the north and north east. The temperature ranges from 4 Degree Celsius to 28 Degree Celsius. In some parts of Rajasthan the temperature may drop to 0 degree Celsius for example in Churu. In Mount Abu it is even below 0 degree Celsius. In winters, you should wear woolen clothes.
The rainfall also varies throughout the state of Rajasthan. Most of the rainfall (60-80%) is received with the South west monsoon in the period from July to September. The average numbers of rainy days vary from 6 to 42 depending on the aridity of the area. Though the average annual rainfall ranges between 200-400 mm, it is as low as 150 mm in extreme arid zones and as high as 1000 mm in the south eastern part of Rajasthan. Some parts of the western Rajasthan receives very little rain, on an average only 100 mm per year. The Aravalli range receives a higher rainfall and lower temperatures throughout the year. While, the south western part of Rajasthan receives a higher rainfall and more humidity.