The temperature sometimes falls below the freezing point in Raj at Ganganagar & Bikaner 2.8ºC. In summer temperature rises above 40ºC Maximum temperature reading 50ºC at Marusthali in Ganganagar.
The mean maximum temperature in My and June is about 45ºC and mean minimum about 23ºC over a large part of Rajasthan. December and January is the coldest month, the mean monthly temperature being 12.9ºC
Rainfall is very low highly erratic and variable throughout the Rajasthan plain mean Annual Rainfall is from 10 cm to 40 cm on eastern edge of Indo-Pak border.
Rainfall decreases from East to West and from South West to North East.
Most of rains occurs in the rainy months of July and August. July to September the three monsoonal months provide 75% to 90% of annual total rainfall. There are years in the heart of Marusthalil where no rainfall occurs.
The highest mean relative humidity is found in months from July to September. It varies between 55% to 70% from March and May. It is lowest varying from 30% to 40% in general.
The mean cloud formation is highest in July and August, varying from 2 to 6. October is cloud free month.
- Dust Storms:
Dust storms are common which suddenly bring down the temperature, causing occasional showers. These storms decrease in no. and intensity towards east.
Ganganagar has on an average 27 days of dust storms during a year, 18 days in Bikaner and 8 days in Jodhpur.
Maximum no. of dust storms occur in June in North West and in May in South and South East.
- Thunder Storms:
Thunder storms show a reverse tuned of spatial distribution. Jodhpur experience 25 days of T.S. in a year and Barmer, Bikaner only 10 days.
The wind blows from west and south west during the hot and rainy season with high velocity.
Climatically, the year in Rajasthan, has been divided into three major conventional seasons.
The Hot-Weather Season:
|Month-||Start in March and prevails from April to June|
|Maximum Temp-||40ºC to 45ºC|
|Humidity-||Decrease by 1%|
|Dust storm-||For 27 days in Ganga nagar 8 days in Jodhpur|
|Pressure-||Falls over heated land|
|Winds-||Dry to warm in April and winds flow from west to east.|
|Rainfall-||Sometime sudden rainfall in this season due to dust storm|
|Day-||Intense heat and glare during the day|
|Night-||Nights even cool in summer|
|Sun is almost overhead from April to May.|