Climate: The basic climatic indices of the Caspian Sea are the followings: Geographical position of the sea, characteristics of atmospheric circulations, influence of nearby terrains (Aral-Caspian lowland in the east, Caucasus ranges in the west) and water exchanges among various parts of the sea. The main distinctive climatic features of the Caspian Sea are as follows: prevalence of anticyclonic weather condition, drastic oscillations of temperature all the year round, cold and windy winter in Northern Caspian, while hot winter in Southern Caspian as well as hot, dry and serene summer for the whole Caspian.
The temperature area on the sea surface in winter is substantially heterogeneous, and temperature is minus in the whole terriory of the eastern portion. Frosts in the sea are observed during October-March, the temperature of January-February is -7°C -11°C on the shore, while - 4°C, -7°C in the sea.
Winter in the Middle Caspian is mild, average monthly temperature during January-February changes from -3°C in the north-east to 3 - 4°C in the south-east, the sea freezing is observed during January-February.
Average temperature of January in the Southern Caspian fluctuates between 3°C in the north-east and 8 -12°C in the south. Tropical cyclones are dominant on the surface of the Caspian Sea during summer months and durable, hot and weak windy weather is able to remain for a long time.
Average monthly temperatures during July-August decrease about 22,3 °C in the northern portion, 24,13°C in the middle portion, 25 - 27°C in the southern portion, and 29°C in the north-eastern portion of the sea.

Monthly temperature oscillations on the surface of the Caspian Sea:
1 – Northern, 2 – Middle, 3 – Southern, 4 – For the whole Caspian Sea

Wind regime: Windstrength is heterogeneous in various regions of the Caspian Sea. The speediest winds (thunderstorms) are observed in the territories of Absheron, Makhachkala and Mangishlag.
The velocity of the wind named “Baku inlet” (local name “Khazry”) in Absheron sea region is more than 30 m/sec, and continuation period exceeds 10 hours. Monsoon and breeze winds are observed especially in the southern part of the sea also due to uneven heating and freezing of the sea environs. Furthermore fen winds blowing from the Caucasus exist in the western coasts of the Middle and Southern Caspian, and in the littoral areas of the mountains. Eastern and south-eastern winds are prevalent in cold months of the Northern Caspian. North-eastern winds vice versa prevail during hot times of the year, probability of eastern, western and north-western winds are the identical. More than 30 m/sec speed winds blow in the direction of mostly north-west. Quantity of stormy days holds 25-30 days during the year.
More than 15 m/sec velocity winds blow mostly in the direction of east and south-east. Recurrence of weak winds (< 6 m/s) holds 60% in summer, while 40 - 45% during other times. Mostly north-western and south-eastern direction winds are prevalent in the western coasts of the Middle Caspian all the year round. Strong winds are typical for Absheron (up to 40 m/sec) and Makhachkala (nearly 35 m/sec) areas, and blow mostly in the direction of north-north-west and south-east, south-west respectively. Average number of stormy days in the western coasts is 70 days during the year, and durational periods reach several days.
Eastern winds are prevalent in the eastern coasts of the Middle Caspian during cold times of the year, while north-western and western winds prevail during hot times. Winds up to 30 m/sec here are observed in the areas of Fort-Shefchenko and Garabogazgyol bay in the directions of east and south-east. Durability period of these winds holds up to 20-24 hours. Recurrence of weak winds in the Middle Caspian (< 6m/sec) holds 40% during autumn and winter, while 55% during spring and summer.
North and north-eastern winds are prevalent in the western coasts of the Southern Caspian during the year, while rare southern and eastern winds prevail during cold periods. Average number of stormy winds holds 12 days during the year. Eastern and north-eastern winds prevail in the eastern coasts, while north-western winds are prevalent during hot periods. Average number of stormy winds here holds 20-40 days annually mostly in spring and early summer.
Recurrence of weak winds (< 6 m/s) in the Southern Caspian holds 44% during fall and winter months, while 60% during spring and summer.

Monthly changes of wind velocity in the Caspian Sea:
1 – Northern, 2 – Middle, 3 – Southern, 4 – For the whole Caspian Sea

Annual numbers of stormy-windy days in the Caspian Sea (speed is more than 15 m/sec)