Examine individual changes

'{{climate chart |[[New Delhi]] | 6.0|21.0| 14.8 | 8.4|24.1| 14.1 |13.6|30.2| 9.3 |20.0|37.0| 6.1 |24.4|40.5| 18.9 |27.5|40.2| 54.2 |26.2|35.1|241.1 |25.3|33.2|284.3 |23.2|33.7|119.4 |18.2|33.2| 16.8 |11.7|28.3| 6.4 | 7.0|22.6| 8.6 |source=[http://www.imd.gov.in/section/climate/palam2.htm IMD] |float=right |clear=none }} The '''climate of [[Delhi]]''' is a monsoon-influenced [[humid subtropical]]I SUCK DICK ([[Köppen climate classification]] ''[[Humid subtropical climate|Cwa]]'') with high variation between summer and winter temperatures and precipitation. Delhi's version of a humid subtropical climate is markedly different from many other humid subtropical cities such as [[Sao Paulo]], [[Tokyo]] and [[Brisbane]] in that the city features [[dust storms]] (something more commonly seen in a [[desert climate]]), has relatively dry winters and has a prolonged spell of very hot weather, causing it to be sometimes classified as [[Semi-arid climate|semi-arid]] region during summers.<ref name="Delhi Climate">{{cite web|title=Delhi Climate|url=http://weatherspark.com/averages/33934/4/15/New-Delhi-India|publisher=Weather Spark}}</ref> Summers start in early April and peak in May, with average temperatures near 32&nbsp;°C (90&nbsp;°F), although occasional heat waves can result in highs close to 45&nbsp;°C (114&nbsp;°F) on some days and therefore higher [[apparent temperature]]. The monsoon starts in late June and lasts until mid-September, with about 797.3&nbsp;mm (31.5&nbsp;inches)<ref name=ecosurv1>{{cite web | url = http://www.imd.gov.in/section/climate/newdelhi1.htm | title = Climatological Table | accessdate = 2009-05-13 | publisher = Indian Meteorological Department }}</ref> of rain. The average temperatures are around 29&nbsp;°C (85&nbsp;°F), although they can vary from around 25&nbsp;°C (78&nbsp;°F) on rainy days to 32&nbsp;°C (90&nbsp;°F) during dry spells. The monsoons recede in late September, and the post-monsoon season continues till late October, with average temperatures sliding from 29&nbsp;°C (85&nbsp;°F) to 21&nbsp;°C (71&nbsp;°F). Winter starts in November and peaks in January, with average temperatures around 12–13&nbsp;°C (54–55&nbsp;°F). Although winters are generally mild, Delhi's proximity to the [[Himalaya]]s results in cold waves leading to lower [[apparent temperature]] due to [[wind chill]]. Delhi is notorious for its heavy fogs during the winter season. In December, reduced visibility leads to disruption of road, air and rail traffic.<ref name=Fog>{{cite news | publisher=The Hindu| url=http://www.hindu.com/2005/01/07/stories/2005010719480300.htm| title=Fog continues to disrupt flights, trains| date=2006-01-07| accessdate=2006-05-16| location=Chennai, India }}</ref> They end in early February, and are followed by a short spring hill the onset of the summer. Extreme temperatures have ranged from &minus;2.2&nbsp;°C to 48.4&nbsp;°C.<ref name="Indian Met Department, Pune">{{cite web|title=Ever Recorded Highest Maximum Temperature, Lowest Minimum Temperature and 24 Hours Heaviest Rainfall upto 2010|url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf|publisher=Indian Met Department, Pune}}</ref> ==Overview of Seasonal Distribution== * Summer: April, May, June; Hot to very hot; Very low to normal humidity (Dry weather); Low precipitation * Monsoon (Rainy): July, August, September; Hot, Pleasant during rains; High to very high humidity; Heavy precipitation * Autumn: October, November; Warm days, Cool nights, Pleasant; Very low to low humidity; Low precipitation * Winter: December, January; Cool to Cold; Low humidity; Low precipitation * Spring: February, March; Warm days, Cool nights, Pleasant; Very low to low humidity; Normal precipitation ==Seasons== Delhi lies in the landlocked [[Indo-Gangetic Plain|Northern Plains]] of the [[Indian Subcontinent]]. Its climate is greatly influenced by its proximity to the [[Himalayas]] and the [[Thar Desert]], causing it to experience both weather extremes. Delhi has 5 distinct seasons, viz. Summer, Rainy, Autumn, Winter and Spring.<ref name="Seasons of Delhi">[http://www.delhitourism.gov.in/delhitourism/aboutus/seasons_of_delhi.jsp]</ref> Broadly speaking, Delhi has long and scorching summers- sub-divided into summer and monsoon seasons, short and cold winters, and two bouts of pleasant transition seasons. Two important occurrences influencing Delhi's climate are [[Western Disturbance]] and [[Monsoon of Indian subcontinent|South-West Winds]]. ===Summer=== Summer begins in early April and continues till the end of June, with the heat peaking in May. It is characterized by extreme heat due to nearly overhead sun, low humidity, very hot winds and at times thunderstorms. Delhi's proximity to the [[Thar Desert]] results in hot, dry continental winds, called [[loo (wind)|loo]], at times blowing all across from the West Asian mainland, making the days feel hotter. These winds, blowing over from vast land stretches, are very hot and dry. Since the [[Western Disturbance]] depression moves eastward (and is the reason for cyclonic occurrences in Eastern Coastal areas) by this time of the year, there is no moisture-laden wind to increase humidity. The air therefore remains dry or very dry during day. For most of its summer season, Delhi has a [[Semi-arid climate|semi-arid]] climate.<ref name="Delhi Climate"/> Coming from Spring, the city witnesses a spurt in day temperature around early April, whereas nights still remain pleasant. By the latter part of April or during early May, maximum temperatures exceed 40&nbsp;°C while the ambience remains very dry. Night temperatures cross the 20&nbsp;°C mark towards the latter part of April. May is Delhi's hottest month during which temperatures may reach 45&nbsp;°C or higher.<ref name="Weather in May in Delhi">[http://weatherspark.com/averages/33934/5/New-Delhi-India]</ref> This month is characterized by frequent [[thunderstorms]].<ref name=NDTV news on Delhi's thunderstorm>[http://www.ndtv.com/article/cities/thunderstorm-cools-delhi-after-scorching-heat-210035]</ref> [[Dust storms]] are an infrequent feature of Delhi's summer.<ref name="A news mentioning Dust Storm in Delhi">[http://www.thaindian.com/newsportal/uncategorized/dust-storm-light-rain-in-parts-of-delhi-lead-2_100617491.html]</ref><ref name=The Tribune's news featuring Delhi's Dust Storm>[http://www.tribuneindia.com/2012/20120513/delhi.htm]</ref> These are caused due to fine dust brought along by the hot winds arriving from the desert. They make the surroundings appear pale yellow, bring temperatures slightly down and are usually followed by [[thunderstorms]]. Post mid-June, temperatures start falling slowly, while humidity shows a gradual rise. A visual characteristic of summer in Delhi is the summer bloom, particularly the blooming [[Bougainvillea]], [[Cassia fistula|Amaltas]], [[Delonix regia|Gulmohar]], [[Albizia lebbeck|Shireesh]] and [[Jacaranda]] trees, which look spectacular when fully flowering during peak summer in May.<ref name="Amaltas bloom in Delhi during May">[http://www.thedelhiwalla.com/2010/05/11/city-season-%E2%80%93-amaltas-tree-hauz-khas-village/]</ref> ===Monsoon=== [[Monsoon]] winds arrive in Delhi by either the end of June or the first week of July.<ref name="Seasons of Delhi"/> The arrival of moisture laden South-Western winds, traveling from the Arabian Sea marks the onset of Rainy season in Delhi. This season is marked by high levels of humidity and high heat. Day temperatures drop below 40&nbsp;°C as humidity suddenly soars.<ref name="Weather in July in Delhi">[http://weatherspark.com/averages/33934/7/New-Delhi-India]</ref> July is marked by high heat and relatively less precipitation. This transition from scorching to sweltering heat between June and July makes the latter feel very uncomfortable. August is Delhi's wettest month. The heat is considerably reduced and it is relatively cooler for most part of the month. There is dense cloud formation in the sky and at least a week of distinct, very heavy rainfall.<ref name="Weather in August in Delhi">[http://weatherspark.com/averages/33934/8/New-Delhi-India]</ref> By September, the amount and frequency of precipitation drops, though humidity remains high.<ref name="Weather in September in Delhi">[http://weatherspark.com/averages/33934/9/New-Delhi-India]</ref> Towards the end of September, moisture content in the air begins to fall and monsoon ends by early October. ===Autumn=== The end of monsoon marks the arrival of a transition season. Autumn arrives by early or mid October, and is marked by very dry ambiance, warm days and pleasant nights. Maximum temperatures drop below 30&nbsp;°C by late October and there is a gradual fall in average temperature. Minimum temperature drops below 20&nbsp;°C.<ref name="Weather in Delhi in November">[http://weatherspark.com/averages/33934/11/New-Delhi-India]</ref> During Autumn, the wind direction begins changing from South-Westerly to North-Westerly. This season ends by early December. ===Winter=== Winter arrives in Delhi in late November or early December. Minimum temperatures gradually enter single digits by this time of the year, while days are pleasant. Though usually not cold initially, December suddenly becomes cold in the latter half, as chilly north-western winds from the [[Himalayas]] begin sweeping the [[Indo-Gangetic Plain|Northern Plains]]. These cold waves are caused by a depression created Plains by [[Western Disturbance]], which bring cloud cover and occasional winter rains to the [[Indo-Gangetic Plain|Plains]], and add to snowfall in the North-Western [[Indian Subcontinent]]. By early January, when winter peaks in Delhi, the minimum temperatures plunge to the vicinity of 0&nbsp;°C,<ref name="1.9°C on a day in 2013">{{cite news| url=http://www.thehindu.com/todays-paper/tp-national/tp-newdelhi/delhi-shivers-at-19-degrees-celsius/article4281551.ece | location=Chennai, India | work=The Hindu | title=Delhi shivers at 1.9 degrees Celsius | date=2013-01-07}}</ref> though rarely entering the negative scale. Maximum temperatures, too may drop down into single digits<ref name="Maximum temperature was 9.8°C on January 2, 2013">[http://www.ndtv.com/article/cities/at-9-8-degrees-celsius-wednesday-was-delhi-s-coldest-day-in-44-years-312479]</ref> and always stay under 20&nbsp;°C. When the minimum temperature ventures very close to the 0&nbsp;°C mark, Delhi witnesses [[frost]].<ref name="News on frost in Delhi in 2006">{{cite news| url=http://articles.timesofindia.indiatimes.com/2006-01-09/delhi/27791060_1_snow-cold-waves-chilly-morning | work=The Times Of India | title=When Delhi woke up to 'snow' - The Times of India | date=2006-01-09}}</ref> [[Snow]], as of now, is a practical impossibility for Delhi (and the rest of [[Indo-Gangetic Plain|Northern Plains]]) due to very dry nature of its winter which is caused because of some [[Siberian High|Siberian Anticyclone]]- like phenomenon{{clarify|date=March 2014}}. Delhi's winter is marked by very dense [[fog]], which dramatically reduces visibility<ref name="An instance of dense fog in Delhi">[http://www.ndtv.com/article/cities/dense-fog-shuts-delhi-airport-affects-86-flights-324996]</ref> and makes days colder by cutting off sunlight. In the opposite scenario, very cold north-westerly winds from upper reaches of Himalayas blowing across the city makes the days feel colder, despite any sunshine and the nights very cold.<ref name="Cold wave forces schools shut in Delhi">[http://www.ndtv.com/article/cities/delhi-schools-to-be-closed-till-january-12-due-to-cold-wave-312966]</ref> Post mid-January, average temperatures begin to rise very gradually, though the rise is almost contained by the cold north-western winds which result due to very heavy snowfall that occurs in the Himalayas during this part of the month.<ref name="Cold wave, slight rise in temperature on January 20, 2011">[http://www.hindustantimes.com/India-news/NewDelhi/Chilly-winds-continue-to-sweep-Delhi/Article1-652545.aspx]</ref> It may rain towards the end of January and the precipitation is usually accompanied by hail,<ref name="Hailstorm in Delhi">[http://www.ndtv.com/article/cities/overnight-rain-hailstorm-lash-delhi-temperature-dips-319026]</ref> resulting in slight increase in minimum temperatures due to cloud cover. Maximum temperatures again cross 20&nbsp;°C and days become pleasant. By mid-February or somewhat beyond, minimum temperature crosses the 10&nbsp;°C mark and days start getting warmer gradually, marking the end of winter. Delhi can sometimes have prolonged season of chill, extending into March; like it had last happened in 2012, when there was chill during March<ref>{{cite news| url=http://www.thehindu.com/news/cities/Delhi/article2981071.ece | location=Chennai, India | work=The Hindu | title=Cool March weather surprises Delhi | date=2012-03-10}}</ref> and Spring-like conditions were prevailing during the summer month of April.<ref name="coldest April in 30 years">[]http://articles.timesofindia.indiatimes.com/2012-05-02/delhi/31537401_1_degrees-maximum-temperature-wds</ref> ===Spring=== Around the middle of February, Delhi's climate sees another transition, this time from Winter to Summer. The transition weather is known as Spring and is characterized by warm days, cool nights, dry ambiance and lively natural surroundings.<ref name="Weather in Delhi in February">[http://weatherspark.com/averages/33934/2/New-Delhi-India]</ref> It is pleasant all time and there is brilliant sunshine during the day. February rains<ref name="2013 had heaviest February rains in 70 years">[http://www.rediff.com/news/report/delhi-receives-februarys-highest-rainfall-in-70-years/20130205.htm]</ref> are a characteristic of this season. These rains may be accompanied by hail and can be heavy. Average temperatures show a slow, gradual rise as the wind direction shift from North-West to South-West, thereby getting warmer. Spring ends by the latter half of March and the day temperatures exceed 30&nbsp;°C by then,<ref name="Weather in Delhi in March">[http://weatherspark.com/averages/33934/3/New-Delhi-India]</ref> marking the onset of the next summer! ==Climate Data and Extreme Temperatures== Temperature records for Delhi exist for a period of a little over 100 years. The lowest ever temperature reading during this period is -2.2&nbsp;°C, recorded on January 11, 1967 at [[India Meteorological Department|Met]] Delhi Palam. And, the highest ever temperature reading during the same period is 48.4&nbsp;°C recorded on May 26, 1998, again at [[India Meteorological Department|Met]] Delhi Palam.<ref name="Indian Met Department, Pune"/> {{Weather box |location = Delhi (Safdarjung), upto 2010 |metric first = yes |single line = yes |temperature colour = pastel |Jan record high C = 30.0 |Feb record high C = 34.1 |Mar record high C = 40.6 |Apr record high C = 45.6 |May record high C = 47.2 |Jun record high C = 46.7 |Jul record high C = 45.0 |Aug record high C = 42.0 |Sep record high C = 40.6 |Oct record high C = 39.4 |Nov record high C = 36.1 |Dec record high C = 29.3 |year record high C = 47.2 |Jan high C = 21.1 |Feb high C = 24.2 |Mar high C = 30.0 |Apr high C = 36.2 |May high C = 39.6 |Jun high C = 39.3 |Jul high C = 35.1 |Aug high C = 33.3 |Sep high C = 33.9 |Oct high C = 32.9 |Nov high C = 28.3 |Dec high C = 23.0 |year high C = |Jan mean C = 14.2 |Feb mean C = 17.1 |Mar mean C = 22.7 |Apr mean C = 28.8 |May mean C = 32.7 |Jun mean C = 33.8 |Jul mean C = 30.8 |Aug mean C = 29.6 |Sep mean C = 29.1 |Oct mean C = 26.2 |Nov mean C = 20.5 |Dec mean C = 15.6 |year C = |Jan low C = 7.3 |Feb low C = 10.1 |Mar low C = 15.4 |Apr low C = 21.5 |May low C = 25.9 |Jun low C = 28.3 |Jul low C = 26.6 |Aug low C = 25.9 |Sep low C = 24.4 |Oct low C = 19.5 |Nov low C = 12.8 |Dec low C = 8.2 |year low C = |Jan record low C = -0.6 |Feb record low C = 1.6 |Mar record low C = 4.4 |Apr record low C = 10.7 |May record low C = 15.2 |Jun record low C = 18.9 |Jul record low C = 20.3 |Aug record low C = 20.7 |Sep record low C = 17.3 |Oct record low C = 9.4 |Nov record low C = 3.9 |Dec record low C = 1.1 |year record low C = -0.6 |precipitation colour = green |Jan precipitation mm = 20.3 |Feb precipitation mm = 15 |Mar precipitation mm = 15.8 |Apr precipitation mm = 6.7 |May precipitation mm = 17.5 |Jun precipitation mm = 54.9 |Jul precipitation mm = 231.5 |Aug precipitation mm = 258.7 |Sep precipitation mm = 127.8 |Oct precipitation mm = 36.3 |Nov precipitation mm = 5 |Dec precipitation mm = 7.8 |year precipitation mm = |Jan record precipitation mm = 20.3 |Feb record precipitation mm = 15 |Mar record precipitation mm = 15.8 |Apr record precipitation mm = 6.7 |May record precipitation mm = 17.5 |Jun record precipitation mm = 54.9 |Jul record precipitation mm = 231.5 |Aug record precipitation mm = 258.7 |Sep record precipitation mm = 127.8 |Oct record precipitation mm = 36.3 |Nov record precipitation mm = 5 |Dec record precipitation mm = 7.8 |year record precipitation mm = |Jan precipitation days = 1.7 |Feb precipitation days = 1.3 |Mar precipitation days = 1.2 |Apr precipitation days = 0.9 |May precipitation days = 1.4 |Jun precipitation days = 3.6 |Jul precipitation days = 10.0 |Aug precipitation days = 11.3 |Sep precipitation days = 5.4 |Oct precipitation days = 1.6 |Nov precipitation days = 0.1 |Dec precipitation days = 0.6 |Jan sun = 213.9 |Feb sun = 217.5 |Mar sun = 238.7 |Apr sun = 216.0 |May sun = 263.0 |Jun sun = 198.0 |Jul sun = 167.4 |Aug sun = 167.6 |Sep sun = 219.0 |Oct sun = 269.7 |Nov sun = 246.0 |Dec sun = 217.3 |year sun = |date=April 2014 |source 1 = ''Indian Meteorological Department, Pune'' (upto 2010)<ref name = HKO >{{cite web | url = http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf | title = Climate Data for Safdarjung observatory, Delhi | publisher = Indian Meteorological Department, Pune}}</ref>}} {{Weather box |location = Delhi (Palam), upto 2010 |metric first = yes |single line = yes |temperature colour = pastel |Jan record high C = 31.0 |Feb record high C = 35.7 |Mar record high C = 41.3 |Apr record high C = 45.3 |May record high C = 48.4 |Jun record high C = 47.6 |Jul record high C = 45.7 |Aug record high C = 43.2 |Sep record high C = 40.8 |Oct record high C = 39.6 |Nov record high C = 36.4 |Dec record high C = 30.0 |year record high C = 48.4 |Jan high C = |Feb high C = |Mar high C = |Apr high C = |May high C = |Jun high C = |Jul high C = |Aug high C = |Sep high C = |Oct high C = |Nov high C = |Dec high C = |year high C = |Jan mean C = |Feb mean C = |Mar mean C = |Apr mean C = |May mean C = |Jun mean C = |Jul mean C = |Aug mean C = |Sep mean C = |Oct mean C = |Nov mean C = |Dec mean C = |year C = |Jan low C = |Feb low C = |Mar low C = |Apr low C = |May low C = |Jun low C = |Jul low C = |Aug low C = |Sep low C = |Oct low C = |Nov low C = |Dec low C = |year low C = |Jan record low C = -2.2 |Feb record low C = -1.6 |Mar record low C = 3.4 |Apr record low C = 8.6 |May record low C = 14.6 |Jun record low C = 19.8 |Jul record low C = 17.8 |Aug record low C = 20.2 |Sep record low C = 13.6 |Oct record low C = 9.9 |Nov record low C = 2.1 |Dec record low C = -1.3 |year record low C = -2.2 |precipitation colour = green |Jan precipitation mm = |Feb precipitation mm = |Mar precipitation mm = |Apr precipitation mm = |May precipitation mm = |Jun precipitation mm = |Jul precipitation mm = |Aug precipitation mm = |Sep precipitation mm = |Oct precipitation mm = |Nov precipitation mm = |Dec precipitation mm = |year precipitation mm = |Jan precipitation days = |Feb precipitation days = |Mar precipitation days = |Apr precipitation days = |May precipitation days = |Jun precipitation days = |Jul precipitation days = |Aug precipitation days = |Sep precipitation days = |Oct precipitation days = |Nov precipitation days = |Dec precipitation days = |Jan sun = |Feb sun = |Mar sun = |Apr sun = |May sun = |Jun sun = |Jul sun = |Aug sun = |Sep sun = |Oct sun = |Nov sun = |Dec sun = |year sun = |date=April 2014 |source 1 = ''Indian Meteorological Department, Pune'' (upto 2010)<ref name = HKO >{{cite web | url = http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf | title = Climate Data for Palam observatory, Delhi | publisher = Indian Meteorological Department, Pune}}</ref>}} ==Weather monitoring stations== Delhi has two weathering monitoring stations, one at Safdarjung inside the main city and other at Palam on its outskirts near the [[Indira Gandhi International Airport|Airport]]. ==Day-length variation== Located at 28°36′36″N [[latitude]], Delhi lies in the temperate region, a few latitudes north of the [[Tropic of Cancer]]. As such the rotation of earth has its effect on the city's day-length, which shortens during winters and lengthens during summers. Between the two [[solstices]], Delhi's day-length changes by about 4 hours, offset by some 2 hours each at sunrise and sunset.<ref>{{cite web|title= Delhi Day length around Summer Solstice|url=http://www.timeanddate.com/worldclock/astronomy.html?n=771&month=6&year=2013&obj=sun&afl=-11&day=1|publisher=timeanddate.com}}</ref><ref>{{cite web|title= Delhi Day length around Winter Solstice|url=http://www.timeanddate.com/worldclock/astronomy.html?n=771&month=12&year=2013&obj=sun&afl=-11&day=1|publisher=timeanddate.com}}</ref> ==Notes== {{Reflist}} [[Category:Geography of Delhi]] [[Category:Climate of India]] [[Category:Climate by city in India|Delhi]]'