Uzbekistan's climate is classified as continental, with hot summers and cool winters. Summer temperatures often surpass 40°C; winter temperatures average about -23°C, but may fall as low as -40°C. Most of the country also is quite arid, with average annual rainfall amounting to between 100 and 200 millimeters and occurring mostly in winter and spring. Between July and September, little precipitation falls, essentially stopping the growth of vegetation during that period.