Climate of Islamabad
The wettest month is July, with heavy rainfall and evening thunderstorms with the possibility of cloudburst.
[4][5][6] 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.
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.
Average rainfall is relatively greater than January totaling to 84.1 millimetres at Chaklala airport and 89mm at Zero Point 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.
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.
Western Disturbance has no timing, it affects the upper and northern parts of Pakistan including Islamabad in every month and season.
A few strong thunderstorms develop every year during this month and sometimes these can accompanied by dust storms and gusts near hurricane force at 126 kilometres per hour (75 mph).
Hailstorms are both greater in frequency and intensity during March and weather can quickly change during the day.
Typically, late April sees a sharp rise in both the day and night time temperatures.
Evening thunderstorms can occur in this month accompanied by dust storms that give the citizens of Islamabad much awaited relief from the scorching heat.
But in the middle of June Pre-Monsoon showers can start that come from South west Monsoon.
[13][14] On 1 June 2016, the most powerful windstorm in the history of Islamabad struck the city with estimated wind gusts of more than 175 km/h causing huge property damage, uprooting large number of trees and poles.
[15] 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.
[17] 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 257 millimetres (10.1 in) occurred that caused flash floods in the city.
On 9 August 2011 a cloudburst in Islamabad that continued for three hours and yielded 176 millimetres (6.9 in) of rain, flooded main streets.
Western disturbances in September can cause strong windstorms with moderate to Heavy Rainfall.
Day temperature can be a bit high, which can cause discomfort in the sun, while travelling and sitting without a fan.
In 2009, Islamabad saw below normal monsoon rainfalls due to the presence of El Niño over Pakistan.
[4][5] Continuous downpour in lasted for about 10 hours from 0600 to 1600 PST in Islamabad,[4][5][6][16] 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.
[40] On 28 July 2021, heavy rains started after the cloudburst in Islamabad, Pakistan, caused flood situation in many parts of the federal capital and killed two people.
[41][42] Several vehicles were swept away in the floods and water entered the basement of houses and plazas in Sector E-11, F-10 and D-12.
This distinct change in climate is the reason experts have classified the Monsoon as a separate season, given its unique nature compared to the typical summer months.
