Climate Overview

Köppen-Geiger Climate Classification, 1991-2020

This page presents high-level information for Iran, Islamic Rep.’s climate zones and its seasonal cycle for mean temperature and precipitation for the latest climatology, 1991-2020. Climate zone classifications are derived from the Köppen-Geiger climate classification system, which divides climates into five main climate groups divided based on seasonal precipitation and temperature patterns. The five main groups are A (tropical), B (dry), C (temperate), D (continental), and E (polar). All climates except for those in the E group are assigned a seasonal precipitation sub-group (second letter). 
The country’s climate is mainly arid and semiarid, except the northern coastal areas and parts of western Iran. The climate is extremely continental with hot and dry summer and very cold winter particularly in inland areas. Apart from the coastal areas, the temperature in Iran is characterized by relatively large annual range, about 22°C to 26°C. The rainy period in most of the country is from November to May followed by dry period between May and October with rare precipitation. The average annual rainfall of the country is about 240 mm with maximum amounts in the Caspian Sea plains, Alborz and Zagros slopes with more than 1,800 and 480 mm, respectively. Iran has climatological diversity with three types of climates: 1) dry and semi-dry climate: large parts of internal lands and southern border of Iran have this climate; 2) Mountainous climate, which itself is subdivided into two categories of cold and moderate mountainous climate; 3) Caspian climate: narrow and small area between Caspian Sea and Alborz Mountain Belt with 600-2000 mm annual rain.

Observed Climatology of Mean-Temperature 1991-2020 Iran, Islamic Rep.

Observed Average Seasonal Mean Temperature

Observed Average Seasonal Minimum Temperature

Observed Average Seasonal Maximum Temperature

Observed Seasonal Precipitation

The identified sub-national units with the highest and lowest precipitation sums reflect the latest climatology, 1991-2020

Trends and Significant Change against Natural Variability

Trends within Variability

Variability and Changes in Variability

Changes and Significance