Effects of Climate on the Form and Elevation of Buildings in Iran
Nazanin Salimi


The characteristics of each climate in Iran
1) Humid & mild climate (Caspian beach)
Caspian beach with temperate weather and a lot of rainfall is considering as a temperate zone. This area is like a band between Caspian Sea and mountain chains of Alborz, with low plains, the more it goes towards the east, the more the more the humidity and the temperate decreases. In fact, Alborz Mountains separates Caspian from the central plateau and creates two different weather conditions. The characteristic of this climate is the high humidity of the weather and temperate weather.
The temperature in summer is between 25º and 30º centigrade, 20º to 23º centigrade at night, and above 0º centigrade in winter, rainfall is very common in the zone and in summer as a rainstorm. Rasht, Anzali, Ramssar, Babolsar and Gorgan are located in this area.

2) Cold climate (west mountains) West Mountains consist of west slopes of the central Mountain chains in Iran. In this area the average temperature in the hottest month of the year is more than 10 degree and the less temperature in the coldest month is -3º centigrade and it is considered as a cold region. West mountain chains, like a barrier, prevent the penetration of Mediterranean humid weather into the Iran Plateau and maintain the humidity in its slopes. One of the characters of this climate is the intense hot in the valleys in summer and it’s mild in winter. The amount and intensity of the sunlight is high in summer and very low in winter. Winter is long, hard and cold and several months of the year, the ice covers the area. In all over of this area, from Azerbaijan to Fars, winter is very hard and the coldness begins from the beginning of November and continues more and less until the end of March. The amount of the rainfall is low in summer and high in winter in the shape of snowfall. Snow covers the mountains in the heights more than 3000 meters. In general, in this zone, the short spring separates winter from summer. Tabriz, Oroumieh, Sanandaj and Hamadan are located in this zone.

3) Warm & dry climate (central plateau) In this climate which consists of the most area of semi equatorial areas, the weather is dry because of the migrate wind from south west & north west to the equator. These winds loose the most humidity while passing through the big continent. In addition, in semi equatorial zones with high air pressure, weather is hot and dry because of moving the higher layer to the down of atmosphere. Because of the dryness of the weather in this zone that is following with another characters, designing constructions is completely based on the weather condition. The sunlight is intense and the sky is without cloud in the most times of the year. But because of the movement of layers near the earth, mist, storm and also dust will appear in the afternoons. The reduction of humidity and also cloud in the sky has caused a big range of air temperature as follows; In summer, the sun light warms up the earth up to 70º centigrade during the day, whereas during the night, the temperature of the earth level decreases quickly and reaches to 15º centigrade and lower.

In central plateau that is the greatest area of Iran and surrounded with high lands, the weather is dry and warm. It has hard and cold winter and warm and dry summers.
Due to the scattered geographical situation in central plateau we can recognize two distinguished semi-desert and desert weather.

     3-1 Semi-desert area The existence of slopes of the mountains of north, west, south, central mountains, and east scattered plateaus has created independent zones due to the central plateaus because of the elevations and the damp of humid wind passes by these elevations. A mild climate in proportion to the central plateau is created and whenever we go from west to east, humid wind decreases while the dry weather increases.

     3-2 desert area Central low plateaus of the east and south east of Iran have desert dry weather. One of the characters of such weather is the high difference of the temperature at night and daytime during the summer. The lowest level of a relative humidity in Iran exists in Dasht Lout area, which is undoubtedly the warmest zone in Iran. Tehran, Meshed, Isfahan and Shiraz are semi-desert cities and Zahedan and Yazd are desert cities too.

4)- Humid and warm climate (south beaches) The south beach of Iran, which has been separated by Zagros mountain chains from the central plateau, has the humid and warm climate. One of the characters of this climate is that the weather is very warm during summer and mild during winter. Maximum temperature in this area in summer is 35º to 40º centigrade and the maximum relative humidity reaches to 10%. The humidity in this climate is high during all season of the year. Therefore the difference of the temperature during night and day time in different seasons is low. The difference of the temperature in beach and sea in these areas has created sea and earth breeze; but this limits to a narrow beach band and the weather is calm in local areas and the speed of the wind is very low. Another characteristics of this climate are the high sun radiation that causes damages to the eyes.

Bandar Abbas, Jask, Abadan and Ahwaz are cities with this climate that are differentiated from each other according to their location in different beaches, their distance to the sea, air humidity and temperature and level of rainfall. In general the level of raining fall in Persian Gulf is higher and more regular, while the Beach of Oman Sea, affected by Indian Ocean winds, has irregular rainfall during the year.