Covering an area of approximately 9,647 km2, the sub-province of Kashan is situated between the Karkas mountains on the west to the Central Desert on the east . The Karkas range divides the sub-province into two distinct topographic and climatic areas: the more temperate western highlands and the arid eastern lowlands. Although the town’s elevation is 950 m above sea level, it still has a warm climate due to proximity to the Central Desert (see Figure 1). The annual average temperature in the town is 19° C, with wide variations in the course of a year that may cover a range of 50° C.Precipitation at Kashan occurs mainly as rain and is concentrated during the winter/spring wet season. The annual rain- and snowfall has been averaged as 137 mm ; as in the case of temperature, the amount of precipitation is subject to wide variation from year to year.
The few rivers flowing from the mountains to the desert are small and temporary. The most important is Šāh-āb, which originates in the Qohrud heights . Irrigation is mainly dependent on the piedmont pockets of water carried to the plains by means of subterranean channels (see kāriz), even if the water is slightly salty. These sources are supplemented by several springs, the most notable of which is the Fin čašma .
The sub-province is generally poor in flora and fauna. The most typical plants are bushes and shrubs spreading over the steppes, but the landscape becomes richer with the increase in elevation. Characteristic trees are pine, cypress, black poplar (kabuda), elm, and ash . Most of the highland’s small forests are already extinct, as the trees have been burned for charcoal (see forests). The sub-province is famous for production of figs and pomegranates from Fin, rosewater from Qamṣar, as well as melons and grapes.