Uzbekistan has an arid and continental climate characterized by large variations in temperature within days and between seasons. Large parts of the country (79% by area) feature flat topography either in the form of semi-desert steppes or desert zones, including desert areas in the far west that have formed as a result of the drying of the Aral Sea. The remaining south-eastern areas have a continental climate, including the area covering the largest cities of Tashkent and Samarkand, and contain high mountains forming part of the Tien-Shan and Gissar-Alai Ranges.
Summers are long, hot and dry, with an average monthly temperature of 27.2°C in the hottest month (July), and with an average daily maximum of 35°C in many of the major cities. Winters are cold, with average monthly temperatures of -1°C to -3°C between December and February. Western areas of the country experience relatively colder winter temperatures, whereas temperatures are highest in the south, near the borders with Turkmenistan and Afghanistan. There is considerable spatial variation in precipitation levels. Many western areas receive less than 100 millimeters (mm) of precipitation per year, whereas parts of the east and south-east can receive up to 800-900 mm per year.
- Average annual air temperatures have risen steadily and significantly in Uzbekistan over the past century, albeit with no variation from year to year. From 1950 to 2013, temperatures rose at an average rate of 0.27°C per decade.
- The average annual temperature range has narrowed in Uzbekistan over the same period, with average minimum temperatures rising by 2.0°C and average maximum temperatures by 1.6°C between 1950 and 2013. The drying, or ‘desiccation’, of the Aral Sea located at Uzbekistan’s Northwestern corner has made a minor contribution to climate warming in the local vicinity.
- Uzbekistan’s rate of warming varied considerably by region, with the steepest rises in temperature occurring in the north and in large cities (0.30°C - 0.43°C per decade), and less warming occurring in mountainous areas (0.10°C - 0.14°C per decade). Warming was fastest in spring (0.39°C per decade) and autumn (0.31°C), while temperature rises were relatively modest in winter (0.13°C per decade).
- In contrast to the clear trend in average temperatures, average annual precipitation has not shown statistically significant changes in Uzbekistan in recent decades.
- A slight decrease in average annual precipitation was observed between 1950 and 2013. Observations from the Tien Shan and Gissar-Alai mountain ranges exhibit some variation between seasons, with a slight increase in winter months (December to February) being offset by slight decreases in other months of the year.