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Karachi has an arid climate, albeit a moderate version of this climate. Karachi is located on the coast and as a result has a relatively mild climate. Karachi has two main seasons; Summer & Winter, while spring and autumn are very short. Summer season persists for longest period during the year. The level of precipitation is low for most of the year. Less precipitation during summer is due to inversion layer. Karachi also receives the monsoon rains from July to September. The city enjoys a tropical climate encompassing mild winters and warm summers. The humidity levels usually remain high from March to November, while very low in Winter as the wind direction in winter is North Easterly. Since summer temperatures (From the end of April till the end of August) are approximately 30 °C (86 °F) to 36 °C (97 °F), the winter months (From November till the end of March) are the best time to visit Karachi. Most visitors, tourists come to Karachi during the month of December.
Contents
Factors
The monsoon and the Western Disturbance are the two main factors which alter the weather over Karachi; otherwise, Continental air prevails for rest of the year. Following are the main factors that affect the weather over Karachi city.
Monthly weather conditions
Like all other cities, Karachi has four seasons, that are Winter, Summer, Autumn and Spring. The spring and autumn, however, are indistinguishable from Summer and Winter since there is no drastic change in temperatures. Summer (March to November) and winter (December to February) are the only prevalent seasons in Karachi, with spring and autumn failing to make their presence felt. Given below is a month-by-month description of the weather prevailing in Karachi:
January
The month of January is the coolest month of the year in the city, with mostly clear skies and a constant N, NE breeze blowing. The influx of very cold and very dry Siberian winds (called "Quetta Waves" in common parlance), bring brief, cold spells to the region, dropping the night temperatures to below 10 degrees Celsius. Western Disturbances from the Persian Gulf and Iran affect the city during this time, bringing with them light rainfall. The highest rainfall during this month was 89.3 millimetres (3.52 in), which was recorded in 1995. The highest temperature of 32.8 °C (91.0 °F) was recorded on 16 January 1965. The average high for the month is 25.6 °C while the average low for the month is a mild 12 °C.
February
The cold waves can affect the metropolis till the middle of the month, after which a warming trend begins in the city. The relative humidity also tends to increase after the middle of the month. The lowest temperature was 3.3 °C (37.9 °F) on 11 February 1950 and the highest was 35.5 °C (95.9 °F) on 10 February 1993. The highest monthly rainfall of 96 millimetres (3.8 in) was recorded in 1979. Western depressions can continue to affect the city during this month, often causing overcast skies and light to moderate rainfall. The intensity of rainfall in February is relatively higher compared to the preceding month. The average high for the month is a pleasant 27.7 °C whereas the lows hover around 15 °C.
March
Weather turns quite warm with the start of March, with increasing humidity and intensity of sunshine. Highest temperature was recorded at 42'C in 2004 and then again in 2010. March is considered spring time in the city, when the skies are usually clear blue and W/SW breeze dominates, making the outdoors much pleasant. Western depressions can bring moderate to at times even heavy rainfall. In the recent years, Karachi has received quite heavy rainfall in the month of March, for instance on 18 March 1997, the city received 25 mm rainfall from an overnight thunderstorm. On 11 March 2007, a strong western depression gave up to 35 mm rainfall in the city, during which intermittent moderate to heavy rain continued in the metropolis from morning till midnight. On 19 March 2007, once again isolated heavy downpour lashed the city, in which the northern parts (North Karachi) received 53 mm rainfall in less than an hour, while other areas received lesser precipitation. Most recently, on 13 March 2015, an overnight dose of heavy rain lashed mainly the southern and SE areas of the city. Between 10 and 15 mm rainfall was recorded in these areas within 15 minutes. However, Gulshan-e-Hadeed observatory (located ESE of the metropolis in the outskirts), received 40 mm downpour on the same night. The all-time high for the month was a mighty 130 millimetres (5.1 in), recorded in 1967, which is March's highest rainfall for the city.
April
Moving into April, the temperatures and humidity see an increasing trend. The highest temperature of April was 44.4 °C (111.9 °F), recorded on 16 April 1947, while the lowest temperature of 12.2 °C (54.0 °F) was recorded on 29 April 1967. The highest monthly rainfall of 52.8 millimetres (2.08 in) was recorded in 1935. The average high for the month is 34.3 °C while the average low is 22.3 °C. Although it is rare for the metropolis to get rainfall in this month, in recent times, April 2013 was quite exceptional as the metropolis was blessed by heavy rain on three occasions: On 2 April 2013, a thunder storm gave heavy rain in northern parts of the city where 12.6 mm rain was recorded. On 8 April 2013, a strong western depression from the Persian Gulf affected the city, giving widespread heavy rainfall in the morning hours, accompanied by strong winds; a maximum of 28 mm rainfall was recorded. On 22 April 2013, a strong thunderstorm ripped across the metropolis at mid-day, giving very heavy rainfall specially in central, NW and southern parts of the city. Downtown (Saddar) observatory in south Karachi received an accumulation of 66 mm for the month, however, the record for the highest rainfall in April stands unbroken because the record of 52.8 mm in 1935 was set at the Airport observatory, while the total rainfall recorded at the Airport in April 2013 was 29 mm. The April 2015 was very warm in Karachi, as it was 2.4 °C warmer on average compared to a standard April.
May
May is the hottest month in Karachi, with temperatures touching 40 °C (104 °F).The highest temperature was recorded on 9 May 1938, when temperatures reached 47.8 °C (118.0 °F) while the lowest temperature was 17.7 °C (63.9 °F), recorded on 4 May 1989. The humidity in the month is quite high, often surpassing 60% and coupled with temperatures ranging between 35-37 °C, the heat indices are generally quite high, making the outdoors highly uncomfortable. Rainfall in May is a rare occurrence. Recently, a very strong thunderstorm affected the metropolis during the early hours of 02 May 1997. 40 mm rainfall was recorded at Masroor Base, while the Airport received 6 mm rain. The highest monthly rain that occurred was in May 1933, when 33 millimetres (1.3 in) rain lashed the city. In 1999, 2001 and 2010, three major cyclones formed that came close to Karachi. The 1999 cyclone (the fourth strongest cyclone of the Arabian Sea) hit close to Karachi, along the coast of Thatta and Keti Bandar giving massive rainfall and causing widespread damage in these areas while the city of Karachi only received very strong NE winds, with light showers (traces). 2001 Indian Ocean cyclone was the third strongest cyclone of the Arabian Sea, that made landfall near the Indian border. Cyclone Phet formed in May 2010, about 1100 km away from Karachi. It travelled along the coast, striking Oman then affecting the coast of Balochistan, giving record-breaking rain amounts there. Gwadar, for instance, got 372 mm rainfall in 36-hours. In May 1902, a cyclonic storm struck the coast in the vicinity of Karachi.
June
The temperatures of June are almost identical to May, with just a slight decrease. The highest temperature of June was 47 °C (117 °F), recorded on 18 June 1979, and the lowest was 22.1 °C (71.8 °F), recorded on 3 June 1997. On 6 June 2010, Cyclone Phet came close to the coast of Karachi as a tropical depression, at about 50 km away from the city after a week-long journey. About 150 millimetres (5.9 in) of rain with 35 mph (56 km/h) winds struck the city. 95 mm rainfall was recorded at the Airport observatory whereas 150 mm was recorded at Masroor Base. That's why once again, the official record for highest rainfall in the month of June, which was set at the Airport observatory in June 2007 i.e. 110 mm, stands unbroken. The average maximum temperature for the month of June is 34.8 °C whereas the average low is 27.9 °C.
Heat Stroke/Heat Wave
June 2015 was incredibly hot and humid in Karachi, being 1.8 °C warmer than an average June in the metropolis. Between 18 June and 23 June 2015, a severe heatwave struck the city; during these days, the maximum temperature remained in the range of 40 °C to 45 °C whereas the minimum temperature was between 30 °C and 33 °C. Due to humidity levels ranging between 40-50%, coupled with high temperature, the heat indices recorded in the city were above 50 °C during these days. The highest temperature during this heatwave was 45 °C (reached first time since 8 June 2000, when the temperature had soared to 45.5 °C), recorded on 20 June 2015, while the minimum temperature on this day was 31 °C. On 21 June 2015, the highest temperature was 43 °C whereas the minimum was 33 °C. The abnormal heat and humidity, coupled with government apathy towards the masses, claimed the lives of 1234 people in Karachi in one week.
July
In the month of July, the city is likely to start receiving rainfall from monsoon systems, that strike the metropolis from the Indian states of Rajhastan or Gujrat. Fast breeze from the W/SW blows throughout the day with stratus clouds covering the sky for most part of the day and night, making the weather very pleasant. Drizzle increases in intensity in this month, mostly occurring during night and early morning hours. At times, showers of considerable intensity can also lash the metropolis from these weak clouds, causing up to a few millimetres of rain. Heavy rains lash the city when a strong monsoon system strikes the region. Average high for the month is 33.1 °C whereas average low is 27.4 °C. The highest July temperature of 42.2 °C (108.0 °F) was recorded on 3 July 1958 and the lowest temperature was 21.2 °C (70.2 °F) on 22 July 1997. The highest monthly rainfall for July was 429.3 mm (16.90 in), recorded in 1967. On 27 July 1944, a cyclone left some 10,000 people homeless in Karachi.
August
The weather of August is identical to that of July. In 2006, after two years of drought (2004 and 2005), widespread rainfall of 77 millimetres (3.0 in) occurred in the city to break the drought period. Between 09 and 11 August 2007, a very strong tropical depression produced 191 millimetres (7.5 in) Intermittent moderate to heavy rain lashed the mega-city during these 48 hours. Another monsoon low produced 80 millimetres (3.1 in) of rain on 22 August 2007 The monsoon typically starts to get weak from the last week of August, but still has the potential to cause heavy rains in the city, as on 31 August 2009, when SE parts of the city received 148 mm rainfall, while precipitation in other areas varied between 40-70 mm. But history has shown that the monsoon withdraws from Karachi during the final days of August. The highest rainfall for August is 272.5 millimetres (10.73 in), which occurred in 1979. The highest temperature was 41.7 °C (107.1 °F) on 9 August 1964, while the lowest temperature was 21.0 °C (69.8 °F), recorded on 7 August 1984. The city's highest rainfall in 24 hours occurred in 1979, when 166 mm rain lashed the city.
September
The first two weeks of September can have some good rains. After the first two weeks, the monsoon completely withdraws from the city, and the sky remains sunny and dry. There is a slight decrease in humidity, which hovers between 70–80%, and an increase in temperatures. Rain in this month is inconsistent. During the monsoon of 2005 no rain occurred in the city raising the fears of drought but from 09 September till 11 September heavy rainfall lashed the city about 80 millimetres (3.1 in) rainfall was recorded. From 12 September evening till 13 September afternoon, 2011 a total of 140 millimetres (5.5 in) occurred in the city that caused urban flooding in almost all parts of the city. The highest rainfall for September was 315.7 millimetres (12.43 in) in 1959. The highest temperature was 42.2 °C (108.0 °F) on 30 September 1951 and the lowest temperature recorded was 18.2 °C (64.8 °F) on 23 September 1994.
October
October is the driest month in the city of Karachi. The highest temperature of 43.3 °C (109.9 °F) was recorded on 1 October 1959 and lowest was 10.0 °C (50.0 °F) recorded on 30 October 1949. Morning is hazy and the winds are calm, the sky remains clear with hot conditions. The highest monthly rainfall for October is 98mm, which occurred in 1956. It is the second hottest month of the year after May. Karachi is considered by some to be a city with two summers. Pre monsoon summer of April–May and post monsoon summer of Sep-Oct. During the year of 2004, the city received no significant precipitation, with the exception of a two-day spell of moderate rain which occurred between 02 and 03 October 2004, due to Cyclone Onil. 35 mm rain was recorded in two days across the city.
November
November has warm days and cool nights. Mid-November conditions are much like those of October. During the last weeks of November there is a gradual decrease in temperature and thus winter begins, but it is not that cold. The first weeks of November are typically dry and the last week of November is cold. It is one of the driest months of the year, not only in Karachi, but most parts of Pakistan. On 9 November 2010 remnants of Cyclone Jal caused gusty winds in the metropolis. The highest rainfall for November is 83.1 millimetres (3.27 in), which occurred in 1959. The highest and lowest temperatures are 38.5 °C (101.3 °F), recorded on 01 November 1994 and 6.1 °C (43.0 °F), recorded on 29 November 1938 respectively.
December
The month of December is the annual winter month, but winter becomes more chilly in January. In December, the weather remains cool. The sky remains overcast for part of the month, causing temperatures to decrease. Rainfall is common in the city during the month of December due to the western disturbance coming from the Mediterranean sea. The highest monthly rainfall of 63.6 millimetres (2.50 in) was recorded in 1980. During December 2006 a strong westerly "low" pressure resulted in 60.5 millimetres (2.38 in) of rain in the city. The highest recorded temperature for December was 34.5 °C (94.1 °F) on 11 December 2001 and the lowest temperature was 1.3 °C (34.3 °F), which occurred on 14 December 1986.
Monsoon precipitation in Karachi
The average annual rainfall for Karachi is 174.6 millimetres (6.87 in) (1981-2010); the highest annual rainfall of 713 millimetres (28.1 in) was recorded in 1967. Annual monsoon rains for Karachi amount to 146.5 millimetres (5.77 in). The city experienced above-normal monsoon rainfalls in 2003, 2006, 2007, 2009, 2010 and 2011, while in 2004 and 2005 the city received below-normal rainfall. In 2009 the country received 30% below normal rainfall with the exception of Sindh, including Karachi, which received above normal monsoon rains. Following is the annual monsoon rainfall for the last few years based on data from the Pakistan Meteorological Department.