Afghanistan is mostly mountainous, having a rugged terrain and an extreme form of continental climate.
The climate of this country is pronouncedly continental. Below is a brief description of its temperature and precipitation.
Temperature in Afghanistan shows extreme variation both in terms of the winter and summer variation and in terms of variation of high and low temperature of a given day. The winter season is excessively cold. At Kabul, the capital, it is usual for the temperature to fall below 14 F (-10 C) in winter. The plain areas like Jalalabad are less cold. Here the temperature rarely fall below 32 F and hovers around 41 F (5 C). The summers, however are hot. At Kabul, despite its elevation of more than 6000 feet above sea level, the mid day thermometer reaches 95 F (35 C) almost every summer. The nights however continue to be cool and in Kabul even during midsummer the night temperatures are around 60 F (16 C). The plain areas, like Jalalabad are, however excessively hot with temperatures frequently reaching 110 F (43 C) or more.
The precipitation throughout Afghanistan is scanty, generally less than 10 inches (250 mm) and is received in cold season. Hills get some snowfall but overall the country is very much deficient in rainfall. This accounts for the ruggedness of the landscape and barren and almost treeless mountains. This deficiency in precipitation is also responsible for the extremes of temperatures which are recorded in Afghanistan.
In a nut shell, therefore the climate of Afghanistan is extreme continental with a meager rainfall which is insufficient to support vegetation of any importance.