Climate of Islamabad

The climate of Islamabad is a humid subtropical climate (Köppen climate classification) with four seasons: a pleasant Spring (March–April), a hot Summer (May–August), a warm dry Autumn (September—October), and a cold Winter (November–February). The hottest month is June, where average highs routinely exceed . The wettest month is July, with heavy rainfall and evening thunderstorms with the possibility of cloudburst. The coldest month is January, with temperatures variable by location. In Islamabad, temperatures vary from cold to mild, routinely dropping below zero. In the hills there is sparse snowfall. The weather ranges from a minimum of in January to a maximum of in June. The average low is in January, while the average high is in June. The highest temperature recorded was in June, while the lowest temperature was in January. On 23 July 2001, Islamabad received a record breaking of rainfall in just 10 hours. It was the heaviest rainfall in 24 hours in Islamabad and at any locality in Pakistan during the past 100 years. Following is the weather observed over Islamabad Airport, which is actually located in Rawalpindi.
Factors.
The Monsoon and the Western Disturbance are the two main factors that change the weather over Islamabad; otherwise, Continental air prevails for rest of the season. Following are the main factors that influence the weather over Islamabad.
Monthly weather conditions.
The following is the monthly summary of the climatic conditions in Islamabad.
January.
January is the coldest month of Islamabad. In January the weather of Islamabad is cold with some nights dropping easily below 0 °C. Most days are clear blue skies, however this month is prone to foggy nights and mornings. Near zero visibility is experienced during extremely foggy nights that absolutely hampers air traffic and motorways. The intensity of Rainfall in this month is moderate to fairly-heavy like in the western disturbance season of the city. Snowfall on higher elevations of Margalla hills is not uncommon as it happens every year or after every few years. There have been rare instances of snowfall in the city (February 1984). The average rainfall for this month is 59mm at Zeropoint official observatory and 56mm at Chaklala (old airport) Western Disturbance has a great influence in the winter of the city. It produces rains and sometimes hailstorms. The highest temperature is (30,Jan,1995) and lowest temperature is . While the highest rainfall for this month is recorded at zeropoint in 1995.
February.
The weather of Islamabad in February is warmer than that of January. The weather remains mild. Western Disturbance causes rainfall just like in January but the frequency and intensity of western disturbances is more than that of January. Average rainfall is relatively greater than January totaling to 84.1 millimetres at chaklala airport and 89mm at Zeropoint official observatory (3.31 in). In 2013, record (Highest) rainfall of 306.1 millimetres (12.05 in) at chaklala airport was observed and a thunderstorms breakout was experienced from three western disturbances that caused bizarre conditions of frequent hailstorms and 93 kilometres per hour (58 mph) wind gusts.[8] Moreover, hailstorms with thunderstorms are not a rare occurrence in this cool time of the year. Observations demonstrate that cold weather (below zero temperature) is not experienced after halfway through the month as plantation season officially begins during the last fortnight. On rare occasions, snowline has even dropped down just to 3000 feet in February because of which Margalla Hills have received heavy snowfall in some years (especially up to a total of 1.5 feet snow in 2005). On 11 February 2016 also, the Margalla Hills received good snowfall which could be clearly seen from the islamabad city. The highest temperature ever recorded was (1985) and lowest temperature is .
March.
Spring starts and in this month, the weather starts to settle. In March the weather turns warmer making it very pleasant. Average relative humidity in this month is about 37%. Again Western Disturbance has an effect on the weather, producing rain and hail. It causes rains with strong winds. Western Disturbance has no timing, it affects the upper and northern parts of Pakistan including Islamabad in every month and season. March 2015 set a record rainfall of a massive 331.1 millimetres (13.04 in) at chaklala airport. A few strong thunderstorms develop every year during this month and sometimes these can accompanied by dust storms and gusts near hurricane force at 120 kilometres per hour (75 mph). Hailstorms are both greater in frequency and intensity during March and weather can quickly change during the day. The highest temperature is and the lowest is . The highest rainfall for March is (2015).
April.
Another Spring month with pleasant temperatures. April in Islamabad transitions from warm to hot during day time, while night temperatures begin to move from cool to warm. Typically, late April sees a sharp rise in the both day and night time temperature. Mean high during day time is 30.2 °C (86.4 °F), while nights enjoy a mean of 15.4 °C (59.7 °F). Record high for April is a very hot 40.6 °C (105.1 °F) recorded on 29 April 2006 at chaklala airport, on the other hand, a chilly low of 5.1 °C (41.2 °F) on 7 April 1994 have been witnessed. The weather at few times gets hot in this month. Humidity remains low in this month about 24%. While the highest rainfall is (1983).
May.
Start of Summers, In May the weather gets very hot in the city. The highest temperature is (1988) and lowest is (1997). Humidity gets extremely low in May as compared to other month, which is of 19%. Evening thunderstorms can occur in this month accompanied by dust storms that give the citizens of Islamabad much awaited relief from the scorching heat. The highest rainfall is (1965)
June.
June is the hottest month of Islamabad. Temperatures in this month reach till as recorded in 2005, While the lowest temperature is (1979). Till the first week of June the weather is very dry. But in the middle of June Pre-Monsoon showers can start that come from South west Monsoon. Dust storms are common in this month which are locally called as "Andhi". The highest rainfall for the month of June is (2008). On 23 June 2010, a massive dust storm of 81 mph (130 km/h) hit the city followed by drizzle before the storm, temperatures peaked above for four consecutive days. On 1 June 2016, the most powerful windstorm in the history of Islamabad struck the city with estimated wind gusts of more than 175kmh causing huge property damage, uprooting large number of trees and poles. Around 30–40 people died in Rawalpindi and islamabad due to that storm.
July.
July is the start of Annual Monsoon season and the wettest month for Islamabad as well as for whole Pakistan that continues till September. In July Islamabad can see some very heavy falls of rain accompanied by Strong Thunderstorms and windstorms. These heavy Storms is due to the moisture coming from Arabian Sea and Bay of Bengal and sometimes if western disturbance interact with them then record rain can be seen. Humidity remains above 65%. The highest temperature in this month is and lowest temperature is and the highest rainfall for this month is recorded at Zeropoint H/8 official observatory in (2001). The heaviest rain of the city was also recorded in this month when rain occurred in just 10 hours on 23 July 2001 the continuous downpour lasted from 0600 to 1600 PST.
In July 2008, a severe rainfall spell, that lasted from 4 to 9 July, produced a heavy rainfall of in 5 hours. It was the heaviest short period rainfall in last six years reminding the cloud burst of 23 July 2001. While on 30 July 2010 heavy downpour of occurred that caused flash floods in the city.
August.
Monsoon rains intensify in August. The month of August is the most humid month for Islamabad. The highest temperature is (1987) and the lowest temperature is (1976). While the highest rainfall for this month is (1982). On 9 August 2011 a cloudburst in Islamabad that continued for three hours and yielded of rain, flooded main streets.the year 2020 also saw record rains and caused havoc.
September.
End of summer in which, day temperatures remain a bit high. But evenings, nights and mornings are quite pleasant. Temperature starts to drop more in the night. And by the end of September, summer seems to have gone away. And Autumn starts to approach. (but in resent years the month has become more hotter)It all depends on the rains. If there are much rains in September, weather will change quickly. If not, then the weather changes gradually. Monsoon rains continue till the first-week of September, but they can be showers till the end of the month. After that monsoon completely withdraws from the city. Western disturbance cause showers or little drizzle in this month. The highest temperature is (1982) and lowest is . The highest rainfall in this month stands at (2014).
October.
The start of Autumn, with pleasant temperatures. Day temperature can be a bit high, which can cause discomfort in the sun, while travelling and sitting without a fan. But evenings, nights and mornings are very pleasant, which urge one to go for walks and for outings. October is the driest month in the city, though in recent years it has been raining a lot. Western disturbance affect the city which causes light rain. Sometimes thunderstorms occur, which cause the temperature to drop more. In the middle of October the night temperature starts to drop very fast and winds start to become very cold which causes more drop in temperature. The highest rainfall for this month is (2015). The highest temperature and lowest temperature is (1998)and (1984) respectively.
November.
Another Autumn and start of Winter Month. The first to second weeks of November are Autumn days. But after that Cold wind start to enter the city. As winter starts by mid November. And temperature starts to drop a lot. Mornings can become very chilly . Warm clothes are pulled out to wear. Some afternoons of November are a bit warm, in which people still avoid direct sunlight. While at times people like to work,play and even stand in the sun. Showers or hailstorms occur in this month too. The highest rainfall for this month is (1959) and the highest and lowest temperature is and respectively.
December.
In the month of December the winter finally sets in, while the coldest winter of the city is observed in January, weather becomes quite chilly in December too. Hot drinks, like tea and coffee with soups become common in the city. Fish is one of the most enjoyed dish of winter. Rainfall in December is expected by western disturbance . Western Disturbance cause rain in this month. The highest rainfall for this month is (1990). The lowest temperature and highest temperature is and respectively.
Monsoon rainfall of Islamabad.
The average monsoon rainfall of Islamabad is . Monsoon season starts by the end of June and prevails till the end of September. In 2009, Islamabad saw below normal monsoon rainfalls due to the presence of El Niño over Pakistan. It just recorded of rain during the Monsoon season in 2009. The highest rainfall of was recorded in Islamabad during 24 hours on 23 July 2001. The record breaking rain fell in just 10 hours. It was the heaviest rainfall in Islamabad in the past 100 years. The following is the Monsoon rainfall in Islamabad since 2006 based on the data from Pakistan Meteorological Department.<ref name="http://www.pakmet.com.pk"></ref>
Cloud burst of 23 July 2001.
On 23 July 2001, Islamabad experienced the record breaking of rainfall, which was the 24 hours heaviest rainfall in Islamabad and at any locality in Pakistan during the past 100 years. Continuous downpour in lasted for about 10 hours from 0600–1600 PST in Islamabad, caused the worst ever Flash Flood in the local stream called "Nulla Lai" and its tributaries, which swept away low-lying areas of the twin cities. The neighbour city, Rawalpindi also experienced of rain on the same day. According to the official figures, at least 10 people died, 800 houses were destroyed and 1069 houses were partially damaged in Islamabad.