Iran covers such a large area of land (approximately 636,369 square miles) that the country contains a vast variety of landscapes and terrains. Much of Iran is made up of the Iranian Plateau, which the exception of the Caspian Sea and Persian Gulf coastlines where the only large plains are found. Iran is also one of the most mountainous countries in the world. These large mountain ranges cut through the landscape and divide the numerous basins and plateaus. The western side of the country possesses the largest mountain ranges such as the Caucasus, Alborz, and Zagros Mountains. The Alborz contains Iran’s highest point on Mount Damavand. The northern part of the country is marked by dense rainforests and jungles, whereas eastern Iran is mostly desert basins which also contain some salt lakes formed due to the mountain ranges that interfere with rain clouds.
Iran has what is considered a variable climate that ranges from semi-arid to subtropical. In the northwest, winters are cold with heavy snowfall and subfreezing temperatures during December and January. Spring and fall are relatively mild, while summers are dry and hot. In the south, however, winters are mild and the summers are very hot, with average daily temperatures in July exceeding 100 degrees (38°C). On the Khuzestan plain, the extreme summer heat is accompanied by high humidity.
In general, Iran has an arid climate in which most of the relatively scant annual precipitation falls from October through April. In most of the country, yearly precipitation averages only 9.84 inches (25 cm) or less. The major exceptions to this semiarid and arid climate are the higher mountain valleys of the Zagros and the Caspian coastal plain, where precipitation averages at least 19.68 inches (50 cm) annually. In the western part of the Caspian, Iran sees the greatest rainfall in the country where it exceeds 39.37 inches (100 cm) annually and is distributed relatively evenly throughout the year rather than being confined to a rainy season. This climate contrasts greatly with some basins of the Central Plateau that receive 3.93 inches (10 cm) or less of precipitation annually where it has been said that “water scarcity poses the most severe human security challenge in Iran today” (UN Resident Coordinator for Iran, Gary Lewis).
Lightweight Cotton clothes are advised in the summer, with a sweater for cooler evenings, especially in the inland areas. waterproof medium wear is recommended for the winter and warmer clothing for the mountainous areas of northern Iran.