Climatology of Pakistan

CLIMATOLOGY OF PAKISTAN

Introduction

Our country is affected by the western disturbance during winters and by the monsoons during summers. The interim periods are caused by the Pre and Post Monsoon periods. Discussed below are the general climatic conditions of Pakistan with a break down of weather conditions during each month of the concerned period.

Western Disturbance period

In this period from December till March, Western disturbance persists in Pakistan. Three to ten inches of rain is received in the Northern parts of the country, where as one to three inches in the southern parts. Temperature ranges on the average between -7 to 20 deg c and visibility is poor in the mornings. Jet stream is present between 28 to 33 deg latitude at about 30,000 feet with wind speed of 150 to 200 kts.

December. Weather is generally good on most of the occasions. Poor visibility due to smoke haze, mist and occasionally radiation fog is a common feature. Precipitation in the form of rain is more in the Northern parts than the Southern parts.

January. The frequency of western wave associated with frontal system is more than that in December. Precipitation is more in the Northern parts than in the Southern parts. Poor visibility remains a common feature and on occasions reduces to few hundred yards after the passage of frontal system.

February. Weather remains much like January; however the frequency of precipitation is more. Northern parts see fog in the morning.

March. Frequent thunderstorms associated with hail occur during this month. Visibility during this month is generally better.

Pre-Monsoon Period

This is an interim period from April to June. Western disturbance moves towards Northern Latitudes; however, one odd occasion may occur during April when Western disturbance causes rain in the North West of Pakistan. A low or a secondary low will develop over Balochistan. Due to surface heating temperatures all over the country rise and pressures fall. The atmosphere becomes unstable and thunderstorms occur frequently; the activity is more frequent in the Northern and Western parts of the country with dust storm in the Southern parts. Temperature increases to 21 to 37 deg C in the North and 45 to 50 deg C in the plains.

April. This is the wettest month of the