Solar Radiation and Sunshine Availability in Rajasthan

Solar Radiation

Rajasthan region receives abundant quantities of solar radiation especially the western parts of the state. The mean duration of bright sunshine in this region is 8.0 to 8.8 hr/day.

  • The maximum sunshine period of 9.6 to 9.8 hr/day is in October for western part of Rajasthan whereas it is 10.0 to 10.5 hr/day during April and May for eastern part.
  • In rainy month of August the sunshine is available only for about 4.4 to 7.1 hrs/day.

Cloudiness

  • In a year, Rajasthan has 300-330 days of clear sunshine.
  • Even during rainy season of July and August, the skies remain clear for 8-9 days/month in west Rajasthan and for 4-5 days/month in east Rajasthan.
  • The cloud cover decreases to a great extent over the entire state during October.

Fog:

  • Fog occurs occasionally due to lack of sufficient moisture in the region.
  • The maximum frequency of occurrence of fog is during December and January in both Western and Eastern Rajasthan.
  • During the monsoon season hill fog occurs at few places, when air is almost saturated and is easily cooled below the dew point while rising over high elevations.

Evapotranspiration

  • The annual potential evapotranspiration values vary widely between eastern and western Rajasthan.
  • In Dungarpur and Banswara districts the annual potential evapotranspiration is less than 1300 mm whereas it is more than 2000 mm in Jaisalmer district.