Depending on the topography, there is an extreme variation in the temperature of Pakistan. The country is essentially arid except for the southern slopes of the Himalayas and the sub-mountainous tract where the annual rainfall varies between 760 and 1270 mm. This area has humid sub-Tropical climate. In the extreme north - because of great heights - Highland climate prevails. The controlling factors of the climate are: 1. The sub-Tropical location of Pakistan that tends to keep the temperature high, particularly in summer. 2. The oceanic influence of the Arabian Sea that keeps down the temperature contrast between summer and winter at the coast. 3. Higher altitudes in the west and north that keep the temperature down throughout the year. 4. The Monsoon winds that bring rainfall in summer.
5. The Western Depression originating from the Mediterranean region and entering Pakistan from the west that brings rainfall in winter. These cyclones make a long land journey and are thus robbed of most of the moisture by the time they reach Pakistan. 6. A temperature inversion layer at a low elevation of about 1,500 m in the south during the summer that does not allow the moisture-laden air to rise and condensation to take place.
Pakistan can be divided into four broad temperature regions: 1. Hot summer and mild winter: 32o C or more in summer and 10 to 21o C in winter. 2. Warm summer and mild winter: 21 - 32oC in summer and 10 to 21oC in winter. 3. Warm summer and cool winter: 21 - 32oC in summer and 0 - 10oC in winter. 4. Mild summer and cool/cold winter: Summer temperature between 10 and 21oC and winter temperature between 0 and 10oC.
The major part of Pakistan experiences dry climate. Humid conditions prevail but over a small area in the north. The whole of Sindh, most of Baluchistan, the major part of the Punjab and central parts of Northern Areas receive less than 250 mm of rainfall in a year. Northern Sindh,...