How does the climate change from the upper Volga River to Astrakhan?

The climate of the Volga River basin undergoes a significant transition from north to south, characterized by increasing temperatures and decreasing precipitation as the river flows toward the Caspian Sea.1

• Upper Reaches: The river's source lies within a temperate climatic zone featuring cold, snowy winters and warm, humid summers. Average temperatures in these upper reaches range from 19 °F (−7 °C) to 6 °F (−14 °C) in winter and 62 °F (17 °C) to 68 °F (20 °C) in July.1
• Lower Reaches (Astrakhan): As the river moves toward its mouth at Astrakhan, the climate shifts to one of hot, dry summers and cold winters with little snow. While winter temperatures remain similar to the upper reaches at approximately 19 °F (−7 °C), summer temperatures are significantly warmer, averaging 77 °F (25 °C).1
• Precipitation and Ice: Annual rainfall drops from 25 inches in the northwest to 12 inches in the southeast. Consequently, the duration of ice cover varies; the river is generally free of ice for about 200 days annually, extending to approximately 260 days near Astrakhan.1