Climate of Rawalpindi

Coordinates: 33°36′N 73°03′E / 33.6°N 73.05°E / 33.6; 73.05 Rawalpindi features a humid subtropical climate (Köppen: Cwa) with long and very hot summers, a monsoon and short, mild and wet winters. Its climate is classified as very similar to its twin city Islamabad, but the geographical location and extreme urbanization of Rawalpindi has led to weather and climatic conditions that are notably different from its twin. Rawalpindi's weather has historically been known to change rather quickly due to its proximity to Himalayas and the Pir Panjal Range. These mountains not only influence the weather of the city but also provide great recreation durin the hot months. Furthermore, Its warm comfortable mean annual temperature attracts people to live here permanently from all over Pakistan. The average annual rainfall is abundant at 1,106 millimetres (43.5 in), most of which falls in the monsoon season. However, frontal cloudbands also bring quite significant rainfall in the winter. In summers, June is the hottest with record maximum temperature at a blistering 46.5 °C (116 °F) recorded on 23 June 2005.^[1] On the other hand, January is the coldest month of the year when temperature can drop to a minimum −3.9 °C (25 °F) in the winter recorded on 17 January 1967. Throughout the year, Rawalpindi and Islamabad experience an average of 89.45 thunderstorms, which is the highest frequency of thunderstorms in Punjab province. In fact, most rainfall in the city is accompanied by a thunderstorm with peak activity experienced in August. Record rainfall was experienced in the year 2007 at a massive 1,828 millimetres (72.0 in) mostly due to an unusually wet monsoon season. On a typical day, the city hosts windy afternoons (40 kilometres per hour (25 mph)+) but usually calm to light breeze (Beaufort scale) wind conditions are observed after midnight. The mean annual wind speed of Rawalpindi is roughly 12 kilometres per hour (7.5 mph) at 10 m standard height. Moreover, just a few kilometers southwest of Rawalpindi the potential power generation has been idenitifed by U.S. Aid to be between marginal to good (5.4 metres per second (19 km/h) to 7.4 metres per second (27 km/h)) at 50 m height.^[2]

Prevailing conditions

Western Disturbance, Monsoon and localized convection currents during the summers are responsible for changing weather conditions in Rawalpindi. Following is a list and conditions provided for the change in weather conditions.

• Western Disturbances occur almost every month in the city, but peaks during the winter months. Not only do these disturbances decrease day and night temperatures but provides the city with rainfall during its dry months. However, by the time these winds reach Rawalpindi, these westerly waves are quite weak in intensity resulting in only light to moderate rainfall. Heavy rainfall from these disturbances are rare. Nonetheless, February 2013 experienced record rains accumulating to a whooping 310 millimetres (12 in)

• Monsoon result in the greatest amount of rainfall in the city and reduces the excruciating heat of the relatively dry summer months. During late June, July, August, and early September southeasterly winds with the intensity of fresh breeze bring along the monsoon clouds and push them against the mighty Himalayas. Most often, rainfall in Rawalpindi doesn't occur until these moisture laden clouds interact with western disturbances producing powerful supercell thunderstorms accompanied with heavy winds, lightning and heavy to very heavy rainfall. Furthermore, these storms can last from 20 minutes to several hours in duration. The highest dew point is experienced during this time of the year with extremely high heat indices.

• Dust storms occur most frequently during the dry heat of May and June, but may well also be occur during the months of late March and April. Dust storms in Rawalpindi are most often accompanied by thunderstorms producing squalls and lightning. Visibilities drop below 100m in extreme cases with wind speeds surpass a fierce 157 kilometres per hour (98 mph).^[3] Rainfall from these storms is generally low to moderate. However, there are instances of extremes on both ends.

• Continental Air prevails during the dry periods of the year with ample sunshine and partly cloudy to clear skies. As high pressure is established atmosphere becomes stable result in no precipitation until a western disturbance intervenes. Strong breeze from westerly direction blow during the day, while nights are calm during this time.^[4]

Thunderstorms

Rawalpindi experiences one of the greatest number of thunderstorms in Pakistan. At a frequency of 89.45 thunderstorms per year on average, these numbers are comparable to that of Florida, USA ^[5] which is quite high. Some of the strongest thunderstorms in the country occur here either accompanied by dusty squalls, microbursts, cloudburst and sometimes even funnel clouds. Its location allows it to experience the maximum wind speed of the storm relative to its twin city Islamabad. On 13 October 2006, wind gusts from a powerful thunderstorm reported by Pakistan Meteorological Department to have reached 167 kilometres per hour (104 mph).^[6] The strongest wind gust during this storm was reported to be 95 knots or 176 kilometres per hour (109 mph), which is the highest recorded wind speed in Rawalpindi/Islamabad region and adjoining areas. As a matter of fact, a funnel cloud was also observed during this storm near Chaklala, Rawalpindi. Tornadoes are rare but have been reported twice in the past decade in 2006 and 2012. The biggest challenge that arises due to these dangerous conditions include fallen trees, downed powerlines, and damage to infrastructure including buildings and billboards around the city.^{[citation needed]}

Monthly conditions

Every month in Rawalpindi is marked by its own unique characteristics, conditions and weather pattern. Following is also a summary of each month's averages and records.

January

January is the coldest month in Rawalpindi with an average low of 3.1 °C (37.6 °F) and a record low of −3.9 °C (25.0 °F) recorded in 1967.^[7] 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. Western Disturbance brings cloudy days, rain and sometimes thunderstorms which are essential for breaking long dry spells in the city experienced during this cool month. Moreover, it eliminates the conditions suitable for the formation of fog at night. Average rainfall for the month sums up to 59.2 millimetres (2.33 in). However, strong thunder/windstorm is uncommon during this month. The average high is 17.6 °C (63.7 °F) while a record high of 30.1 °C (86.2 °F) has been recorded. Strong winds blow from the west during most clear days, but nights are calm with cool to cold temperatures.

February

February experiences similar weather to January except that usually it is a few degrees warmer. Most nights are cool and days are warm with an average low and high of 5.4 °C (41.7 °F) and 19.2 °C (66.6 °F), respectively. Overcast for several days is not uncommon during this month with the least amount of sunshine experienced during this month. A record high of 30.0 °C (86.0 °F), while the coldest −2.0 °C (28.4 °F)^[7] have been recorded in February. Average rainfall is relatively greater than January totaling to 79.7 millimetres (3.14 in). In 2013, record rainfall of 306.1 millimetres (12.05 in) 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 half way through the month as plantation season officially begins during the last fortnight.

March

March has a splendid spring time feel in Rawalpindi with perfect warm temperatures of 23.7 °C (74.7 °F) during the day and cool crispy night temperatures averaging to 10.1 °C (50.2 °F). Record maximum and minimum is 34.4 °C (93.9 °F) and −0.3 °C (31.5 °F), respectively. As spring season begins to settle, rainfall also increases from Western Disturbances accumulating to 97.1 millimetres (3.82 in). 1981 set a record rainfall of an impressive224 millimetres (8.8 in). A few strong thunderstorms develop every year during this month and sometimes these can accompanied by heavy 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.

April

April in Rawalpindi 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 40.2 °C (104.4 °F), on the other hand, a chilly low of 5.4 °C (41.7 °F) have been witnessed. Western Disturbance is responsible for localized rainfall during this month, but typically these systems are not as strong as during March since rainfall totals 63.1 millimetres (2.48 in). Moreover, thunderstorms often cause horrid dust storms that become a frequent occurrence as the weather becomes drier, transitioning into summer. One such thunderstorm was blamed for the disaster of Bhoja Air jet, flight BHO-213 when a lightning strike or wind shear was blamed for the tragedy.^[9] A full report has yet to be released to the public. Heavy rain showers are rare during this month as dust storms frequently only cause drizzle or light scattered rain that makes the weather pleasant.

May

As May begins day time temperatures begin to rise and the day and night time temperature range is high during this time. It is categorized as a hot dry month with a record maximum of 45.6 °C (114.1 °F) experienced on 31 May 1988. Furthermore, during the record breaking heat wave of 2013 in Pakistan, near record temperature of 45.5 °C (113.9 °F) was recorded on 24 May 2013. This heat wave witnessed an average high of 37.4 °C (99.3 °F) which is 1.8 degrees higher than its average high of 35.6 °C (96.1 °F). Average minimum stands at 20.1 °C (68.2 °F). Nevertheless, night time temperatures during heat waves could remain well above 28.0 °C (82.4 °F). Mid-May and June typically are the dry heat season. Thunderstorms that occur are typically strong, accompany heavy dust with blinding visibility and wind speed in excess of 130 kilometres per hour (81 mph) in some storms. These storms truly testify as "Kali Andhi", a common phrase used by the locals. Most storms occur during night time that brings relief from the relentless heat of the day. Rainfall however is scanty as the mean is only 34.1 millimetres (1.34 in), while 1965 was the wettest May at 115.3 millimetres (4.54 in). Wind speeds during this month are the second highest averaging to more than 16 kilometres per hour (9.9 mph).

June

June is undoubtedly the hottest month of the year. Most day time temperatures are excruciatingly hot with the maximum record temperature of 46.6 °C (115.9 °F) recorded on 23 June 2005. Heat waves experienced during this season often raises temperature to over 45 °C (113 °F). Nights are warm at an average of 23.5 °C (74.3 °F); however, during heat waves night time temperatures may not fall below 30 °C (86 °F) and begin to rise again soon after sunrise. Thunderstorm activity is high and the city often experiences severe thunderstorms during this month. Rainfall for June averages 98.4 millimetres (3.87 in) and comes from both western disturbances, localized thunderstorms and monsoons. Record breaking wind speed for June was recorded on 5 June 2003 when a wind/thunderstorm broke havoc in the city with gusts up to 90 knots 167 kilometres per hour (104 mph) that caused most of the city to lose power and property damage. These powerful thunderstorms develop as a result of moist warm monsoon winds colliding with cool dry western disturbance creating monstrous thunderstorms accompanied with powerful microburst that cause extensive damage to billboards, pylons, roofs, crops and trees. Unfortunately, every year these wind storms kill as well.^{[citation needed]} One such microburst of 85 knots was recorded by a weather station at Chaklala on 12 June 2012.^[3] Usually, late June welcomes the monsoon season which causes dew point to rise, and wind direction shifts from west to southeast. Relative humidity increases from these southeasterly winds that causes great discomfort without air conditioning as head indices (feels like) can rise in excess of 50 °C (122 °F). In 2008, the city experienced record rainfall of 255 millimetres (10.0 in). The month of June is also the windiest of all with an average wind speed of 17 kilometres per hour (11 mph).

July

July is the second wettest city with an average rainfall of 305.3 millimetres (12.02 in) as the monsoon activity increases. The highest rainfall ever recorded in a month accumulated to 743.3 millimetres (29.26 in) recorded in 1995 with very dramatic weather as rain was brought by severe thunderstorms and cloudburst. The highs are relatively cooler than June, but the heat index (feels like temperature) makes the heat all the more blistering with southeastern monsoons winds increasing dew point up to 28 °C (82 °F).^[10] The average high temperature for July is 36.4 °C (97.5 °F) categorized as hot, an extreme of 45.4 °C (113.7 °F) have been recorded in past 70 years. Nights are also warm at an average 23.5 °C (74.3 °F) since the temperature range is small during these humid months. Thunderstorm activity is the second highest during this month but interestingly, most of the rumbling and anger of the clouds is heard at night. Rain showers can be extremely heavy at times especially during cloudburst events. Unprecedented flooding cannot be ruled out during such events. One such cloud burst took the twin cities by surprise also known as the 2001 Islamabad cloud burst, brought historic flash floods in the stream of "Nullah Lai" and brought tragic scenes to the city. This 100-year storm dropped Pakistan's highest 24 hour rainfall ever reported in the neighboring city of Islamabad accumulating to an astounding 620 millimetres (24 in), while Rawalpindi received 335 millimetres (13.2 in) during the same storm.^[11]

August

August is the wettest city with an average rainfall of 348.1 millimetres (13.70 in) as the monsoon peak during this month. August is a hot and humid month, however, thunderstorm activity reaches its peak primarily due to the monsoon. On average a thunderstorm happens every other day also attributing it as the second wettest month of the year. Slightly lower mean maximum temperature of 33.4 °C (92.1 °F) is recorded, while average minimum of 23.6 °C (74.5 °F) has been observed. Record high temperature for August is 42 °C (108 °F) and the record low is 17 °C (63 °F). Similarly to July, some of the strongest thunderstorms are formed during this month that result in severe wind storms. One such powerful thunderstorm was reported from Northerly direction on 26 August 2005, which not only caused most of the city to lose power, but motorists faced hazardous conditions due to falling trees. [Pakistan Meteorological Department] recorded wind gusts of 90 knots or 167 kilometres per hour (104 mph). Record rainfall for the month is a massive 641.4 millimetres (25.25 in) recorded in 1982.^[7] Furthermore, its not unusual to experience 150 millimetres (5.9 in)+ rain showers within 24 hours during July and August. Flooding in lower elevations of the city is common as well. The temperature by mid August becomes comfortable enough that plantation season begins in the city.

September

September is cooler and relatively less humid than the subsequent two monsoon months. It is referred as a post monsoon month, which usually entertains less moisture than the peak season. However, Western Disturbance interact more with the monsoons during this month resulting in strong thunderstorm activity and heavy wind and rain along. Not only do the temperatures begin to decrease from August, but the drop in humidity makes the outdoors more comfortable. This month holds plenty of sunshine as the average high of 33.5 °C (92.3 °F) while average low is recorded at 20.7 °C (69.3 °F) Rainfall during this month is plenty at 112.2 millimetres (4.42 in). the record high and low temperature is 38.1 °C (100.6 °F) and 13.3 °C (55.9 °F), respectively.

October

October is a warm and dry month with plenty of sunshine throughout the day. Humidity drops rapidly as the monsoons recede from the country and is replaced by strong westerly winds. Typically, wind speed increase around noon and usually dies down by night time. However, these winds are dry as western disturbance activity also drop significantly. Some of the lowest relative humidity values are experienced during this month. Therefore, average rainfall is scanty at 26 millimetres (1.0 in) Temperature range is high during this month as nights begin to enter the cool temperature range with warm sunny days. The average low is a cool at 14 °C (57 °F) while a warm 30.9 °C (87.6 °F) is the average high. Record high for the month is hot 36.9 °C (98.4 °F) and a record low of 5.7 °C (42.3 °F) has been recorded.

November

November is the driest month of the year as the mean rainfall is barely 15.6 millimetres (0.61 in). This month therefore receives the greatest amount of sunshine as overcast days during both October and November are very rare. Moreover, November demonstrates a continuation of very similar weather pattern observed in October, but with significantly cooler day and night temperatures. A few thundershowers cool down the weather further and officially sets cold weather during this month. The average low for November is 7.9 °C (46.2 °F). Day temperature however due to high temperature range, is still in the warm range at an average of 25.9 °C (78.6 °F) Record low for this month −0.6 °C (30.9 °F) and a record high of 32.2 °C (90.0 °F) has been recorded.

December

December is the second coldest month in Rawalpindi after January with a record low temperature of −2.8 °C (27.0 °F). The average low for the month is a chilly 4.0 °C (39.2 °F), while comfortable highs of 20.0 °C (68.0 °F) are typically recorded during the day. The record high has been recorded at 28.3 °C (82.9 °F). Typically on a sunny day temperature range during the last three months can be in excess of 20 °C that results in the comfortable outside temperature during day time. It is not uncommon for people of all age groups to enjoy the afternoon and evening sun because of its irreplaceable warmth. Western Disturbance begin to affect the city more frequently during this month, but strong thunderstorms during this month is rarely experienced. Mean rainfall is increases slightly from the month of November to 31.2 millimetres (1.23 in). The dominant wind direction remains west during the day with gust speeds between 35 kilometres per hour (22 mph) to 45 kilometres per hour (28 mph).

Heat island effect

Like most major cities of Pakistan, Rawalpindi not only lack vegetation, but experiences a phenomenon known as the Urban Heat Island. Urban Sprawl and lack of adequate vegetation has witnessed a rise in both day and especially night temperatures. Although some of the above normal temperatures can be attributed to climate change. However, in comparison to its green neighbour Islamabad, Rawalpindi can experience nights up to 3-5 °C warmer.

See also

• Climate of Islamabad
• 2001 Islamabad cloud burst
• Climate of Pakistan
• List of extreme weather records in Pakistan

References