The climate of Pakistan has traditionally been defined based either on the four seasons that is summer, winter, spring and fall or in terms of Pre monsoon, Monsoon, Post monsoon and winter as defined by Meteorological organizations in South Asia. The climatic features of the country, however are too diverse and complex to conform to the above mentioned nomenclatures.
There is a dire need to redefine the climatic zones based on cash crop output; Pakistan being an agro-based economy. For this purpose following climatic Zones are proposed:
The Rain Fed or Barani Zone
This is a narrow strip like zone in Northern Pakistan that consists of about 10 percent of the total land area of Pakistan and comprises of Rawalpindi, Hazara, Gujranwala divisions and Kashmir. The general climatic features are absence of any prolonged heat spell, moderate temperatures both in summer and winter compared to other areas of Pakistan, no prolonged hygrothermal stress for crops and reliable rainfall all the year round. This area is so located geographically that it gets benefit both from the western disturbance and the monsoon systems.
The Canal Fed Zone
This zone consists of the upper and lower Indus Plain. The general climatic features are cool winters and exceptionally hot summers with moderate to high hygrothermal stress to cash crops. The rainfall is not very deficient but is inappropriate to support crops on its own. So the deficit is met with the excellent canal system present in the area. This climatic zone accounts for 30 percent of the total area of Pakistan.
The Arid North and North West Zone
This consist of whole of the Baluchistan plateau, and dry mountains of the North and North West. The general features are extreme dryness, extreme winter cold, a total absence of monsoon rain fall and high hygrothermal stress for the crops. In fact the temperatures and the humidity figures reach to such an extreme to render any sort of agriculture activity practically impossible. This climatic zone accounts for 55 percent of the total land area of Pakistan.
The Arid Coastal Zone
This consist of a very narrow area along the southern coast of Pakistan that accounts for 5 percent of the total land area of Pakistan. There is practically no rainfall both in winter and summer. The humidity is high throughout the year. The temperatures remain high throughout the year. There is no canal system in the area and no fresh water source is located nearby. This area is also not fit for any sort of agriculture.
In short, a strong needs exists to redefine the climatic zones of Pakistan based on agriculture; Pakistan being an agro-based economy.