Azerbaijan’s climate is highly varied, with different areas of the country containing examples of nine of the world’s eleven climate zones. This includes semi-arid zones in the center and east of the country (including the capital, Baku), temperate zones in the north, continental zones in the west, and tundra zones, meaning that there are marked variations in average annual temperature and precipitation in different regions. In general, more mountainous parts of Azerbaijan receive higher levels of precipitation and lower average temperatures than the central lowlands and Caspian Sea coast, where the climate is drier and hotter. Azerbaijan experiences hot summers (especially in lowland areas) and moderate winters. The average monthly temperatures vary significantly between different regions and altitudes across Azerbaijan. Average temperatures in Baku and other parts of the east and southeast reach approximately 27ºC during the hottest months of July and August, while temperatures during these months remain between 15ºC and 20ºC in parts the mountainous north and west. Similarly, during the winter (December to February) temperatures in Baku average between 3ºC and 4ºC, whereas in western and northern areas average monthly temperatures fall to between −5ºC and −10ºC. Average rainfall in Azerbaijan follows a bimodal distribution throughout the months of the year, with average levels above 40 millimeters (mm) per month from April to June, and again in October. Precipitation is highest in May and June in the northern and western areas of Azerbaijan, where it can exceed 100 mm per month.
- Azerbaijan’s NC3 reports an increase in temperatures across the country of 1.3ºC, relative to the average annual temperatures observed in the period 1961–1990.
- Increases in annual average temperatures was more acute in areas of higher altitude (>1,000 meters [m]), where temperatures were 1.9ºC above their 1961–1990 levels.
- Increase in temperature was observed mainly during summer season which was about 0.9ºC in Absheron-Gobustan region, 1.1ºC in Lesser Caucasus region, 0.8ºC in Lankaran-Astara region and 0.9ºC in Kura-Araz region. Increase in temperature in Nakhcivan region was observed in summer and autumn seasons (0.8ºC).
- Annual anomaly of temperature was observed mainly in Ganja (1.1ºC) and Dashkasan (1.2ºC) stations of Lesser Caucasus. In line with these temperature increases, glacial loss over the period 1906–2006 in Azerbaijan was approximately 50%.
- Trends in precipitation in Azerbaijan are variable with a degree of uncertainty. The amount of precipitation, seasonal and annual is determined by the interaction of air masses with the landscape and the Caspian Sea.
- The Southern shore of the Absheron Peninsula and Southeast of Gobustan traditionally receive the minimum average annual precipitation (150–200 mm per year). The Southeastern lowlands of Samur-Davachi, Araz plain of Nakhchivan AR, main parts of Gobustan and Absheron Peninsula precipitation experience less than 300 mm. Precipitation gradually increases from the Caspian Sea to the west and increases up the mountains and can experience as much as 1,400 to 1,600 mm.
- While the majority of the precipitation coincides with the warm period (April-October), summer months are mostly dry and even the annual precipitation rate in the Lankaran-Astara, a region with abundant precipitation, diminishes by 5–15%.