|Most of Afghanistan has a subarctic mountain climate
with dry and cold winters, except for the lowlands, which have arid and
semiarid climates. In the mountains and a few of the valleys bordering
Pakistan, a fringe effect of the Indian monsoon, coming usually from the
southeast, brings moist maritime tropical air in summer. Afghanistan has
clearly defined seasons; summers are hot and winters can be bitterly cold.
Summer temperatures as high as 49 °C (120 °F) have been recorded in the
northern valleys. Midwinter temperatures as low as -9 °C (15 °F) are
common around the 2000-m (6600-ft) level in the Hindu Kush. The climate in
the highlands varies with elevation. The coolest temperatures usually
occur on the heights of the mountains.
Temperatures often range greatly within a single day. Variations in
temperature during the day may range from freezing conditions at dawn to
the upper 30s °C (upper 90s °F) at noon. Most of the precipitation falls
between the months of October and April. The deserts receive less than 100
mm (4 in) of rain a year, whereas the mountains receive more than 1000 mm
(40 in) of precipitation, mostly as snow. Frontal winds sweeping in from
the west may bring large sandstorms or dust storms, while the strong solar
heating of the ground raises large local whirlwinds.