Half of the annual rainfall occurs in July and August, averaging about 255 millimeters in each of those two months.
According to the government, 40 percent of the country's water needs went unmet.
Pakistan has seen many floods, the worst and most destructive is the recent 2010 Pakistan floods, other floods which caused destruction in the history of Pakistan, include the flood of 1950, which killed 2910 people; on 1 July 1977 heavy rains and flooding in Karachi, killed 248 people, according to Pakistan meteorological department 207 millimetres (8.1 in) of rain fell in 24 hours.
Evenings are cool; the diurnal variation in temperature may be as much as 11C to 17C.
Winters are cold, with minimum mean temperatures in Punjab of about 4 °C (39 °F) in January, and sub-zero temperatures in the far north and Balochistan.
According to the Economic Survey of Pakistan, the drought was one of the most significant factors responsible for the less than anticipated growth performance.
The survey terms it as the worst drought in the history of the country.The highest rainfall of 620 millimetres (24 in) was recorded in Islamabad during 24 hours on 24 July 2001. It was the heaviest rainfall in Islamabad in the previous 100 years.Each year before the onset of monsoon that is 15 April to 15 July and also after its withdrawal that is 15 September to 15 December, there is always a distinct possibility of the cyclonic storm to develop in the north Arabian Sea.Very high altitudes modify the climate in the cold, snow-covered northern mountains; temperatures on the Balochistan Plateau are somewhat higher.Along the coastal strip, the climate is modified by sea breezes.Only July and August average more than twenty-five millimeters of rain in the Karachi area; the remaining months are exceedingly dry.The temperature is also more uniform in Karachi than in Islamabad, ranging from an average daily low of 13 °C during winter evenings to an average daily high of 34 °C on summer days.The weather extremes in Pakistan include high and low temperatures, heaviest rainfall and flooding.The highest temperature ever recorded in Pakistan is 53.5 °C (128.3 °F) which was recorded in Mohenjo-daro, Sindh on .Pakistan recorded one of the highest temperatures in the world – 53.5 °C (128.3 °F) – on , the hottest temperature ever recorded in Pakistan, but also the hottest reliably measured temperature ever recorded on the continent of Asia.As Pakistan is located on a great landmass north of the Tropic of Cancer (between latitudes 25° and 36° N), it has a continental type of climate characterized by extreme variations of temperature, both seasonally and daily.