Semnan is one of the cities of Iran and is the capital of Semnan province. This city is located south of the Alborz Mountains and north of Loot Desert along the Tehran road to Khorasan. The climate is dry and temperate. Distance from Semnan to Tehran is 216 km and it’s connected to Tehran-Mashhad railway, and has two airports (one commercial and one military). Semnan is the most populous city in Semnan province. The race of the people of Semnan are Aryan and they speak Persian and Semanani languages.
The weather is warm in the summer and relatively cold in winter. The rainfall is in the cold seasons, with an average annual rainfall of 140 mm.
The average annual temperature is 17.7 ° C, while the maximum absolute temperature is 44.5 ° C and the minimum absolute is -6.4 ° C. Also, the average number of ice days per year is about 48 days.
In the south of Semnan, areas such as Loot Desert, Rige Jen, Hesar Hills, Dalyazian Hill and Mirq Dalliazian Hills are among the most important geographic features.
The River Gol Rudbar is in the northwest of the city and originates from the Alborz Mountains and passes through the city of Mahdishahr and goes to Loot Desert. Gol Rudbar River originates 3 km west of Bakhtar Mahdishahr, and the rivers of Dehsoufian, Shahmirzad, and Kariza villages in Dzhazin connect to this river. In the north of Semnan, the river Golrud is divided into 5 branches in the place which is called “water distributor”.