Climate of Delhi: Difference between revisions

Winter starts in  November  and peaks in January, with average temperatures around {{convert|6|-|7|C|F}}. Although winters are cold, 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 and haze during the winter season. In December, reduced visibility leads to disruption of road, air and rail traffic.<ref name=Fog>{{cite news

Extreme temperatures have ranged from {{convert|-2.2|to|48.4|C|F}}.<ref name="Indian Met Department, Pune">{{cite web|title=Ever Recorded Highest Maximum Temperature, Lowest Minimum Temperature and 24 Hours Heaviest Rainfall up to 2010 |url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf |publisher=Indian Met Department, Pune |url-status=dead |archiveurl=https://www.webcitation.org/6GmnoaB0m?url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf |archivedate=2013-05-21 }}</ref>

{{Schemebox|city=Delhi|description_t=[[Aw climate|Tropical wet-and-dry]]|initial_t=<center>Aw</center>|source_t=<ref>{{Cite web|url=https://kkh.ltrr.arizona.edu/kkh/climate/trewartha_maps.htm|lang=en|access-date=2020-11-30|title=Trewartha Maps}}</ref>|source_s=<ref>{{Cite web|url=https://i.pinimg.com/originals/c5/16/b8/c516b8c463fa99df0da778f768c85965.jpg|title=World Strahler Climate Map}}</ref>|initial_s={{n/a}}|description_s=Dry tropical semi-arid|description_k=Monsoon-influenced humid subtropical|initial_k=<center>Cwa</center>|source_k=<ref>{{Cite journal|last1=Chakraborty|first1=Surya|last2=Kant|first2=Yogesh|last3=Mitra|first3=Debashis|date=22 November 2013|title= Assessment of land surface temperature and heat fluxes over Delhi using remote sensing data|journal=Journal of Environmental Management|language=en|volume=148|pages=143–152|doi=10.1016/j.jenvman.2013.11.034|pmid=24360191}}</ref>|source_n=<ref>{{Cite web|url=http://www.geo.tu-freiberg.de/hydro/aral/aral_en/climate.htm|access-date=2020-11-30|lang=en|title=The Climate of Lake Aral}}</ref>|initial_n={{n/a}}|description_n=Tropical alternating climate equatorial climate|source_a=<ref>{{Cite journal|last=Eguchi|first=Takashi|date=1986|title=Global Climatic Classification Based on Seasonal Distribution of Non-Precipitation Areas|volume=59|issue=1|pages=43–54|language=en|journal=Geographical Review of Japan|url=https://www.jstage.jst.go.jp/article/grj1984b/59/1/59_1_43/_pdf}}</ref>|initial_a={{n/a}}|description_a=Sub-equatorial climate|source_tw=<ref>{{Cite journal|last=Feddema|first=Johannes J.|date=January 2005|title=A Revised Thornthwaite-Type Global Climate Classification|journal=Physical Geography|language=en|volume=26|issue=6|pages=442–466|doi=10.2747/0272-3646.26.6.442|s2cid=128745497|issn=0272-3646}}</ref>|initial_tw=<center>DA'd</center>|description_tw=[[Semi-arid climate|Semi-arid]] and [[megathermal]]}}

* Summer: April, May; hot to very hot; very low to moderate humidity; low precipitation

* Monsoon (Rainy): June, July, August, September; hot, pleasant during rains; high to very high humidity; heavy precipitation

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. Spring, Summer, Rainy, Autumn and Winter.<ref name="Seasons of Delhi">{{cite web | url=http://www.delhitourism.gov.in/delhitourism/aboutus/seasons_of_delhi.jsp | title=Seasons of Delhi | publisher=Delhi Tourism | accessdate=17 June 2018 }}</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 most important wind patterns influencing Delhi's climate are the [[Western Disturbance]] and the [[Monsoon of Indian subcontinent|South-West Winds]].

 

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>{{cite web|title= Weather in Delhi in February|url=http://weatherspark.com/averages/33934/2/New-Delhi-India}}</ref> The weather is pleasant and there is warm, brilliant sunshine during the day. Spring rains<ref>{{cite web|title= 2013 had heaviest February rains in 70 years|url=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. Around late spring/ early summer, the variation between morning and afternoon temperatures in a day becomes considerable, and can often be more than {{convert|20|C|F}}, with maximum rising to mid 30s&nbsp;°C ({{convert|34|-|36|C|F|disp=out}}) and minimum in the mid 10s&nbsp;°C ({{convert|14|-|16|C|F|disp=out}}). Spring ends by the latter half of March and the day temperatures exceed {{convert|30|C|F}} by then,<ref>{{cite web|title=When it rains during the spring season, day temperatures hardly cross 24 degrees Celsius while nights remain relatively cold at about 13 degrees Celsius Spring can often have cold waves resulting in low temperatures dropping to about 9 degrees Celsius in early march Weather in Delhi in March|url=http://weatherspark.com/averages/33934/3/New-Delhi-India}}</ref> marking the onset of the next summer.

Summer begins in early April and continues till the middle of June, with the heat peaking in late May/early June. It is characterized by extreme heat, low humidity, very hot winds and 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 {{convert|40|C|F}} while the ambience remains very dry. Night temperatures cross the {{convert|20|C|F}} mark towards the latter part of April. May is Delhi's hottest month during which temperatures may reach {{convert|45|C|F}} or higher.<ref>{{cite web|title= Weather in May in Delhi|url=http://weatherspark.com/averages/33934/5/New-Delhi-India}}</ref> This month is characterized by frequent [[thunderstorms]].<ref>{{cite web|title= NDTV news on Delhi's thunderstorm|url=http://www.ndtv.com/article/cities/thunderstorm-cools-delhi-after-scorching-heat-210035}}</ref> [[Dust storms]] are another feature of Delhi's summer,<ref>{{cite web|title= A news mentioning Dust Storm in Delhi|url=http://www.thaindian.com/newsportal/uncategorized/dust-storm-light-rain-in-parts-of-delhi-lead-2_100617491.html}}</ref><ref>{{cite web|title= The Tribune's news featuring Delhi's Dust Storm|url=http://www.tribuneindia.com/2012/20120513/delhi.htm}}</ref> and can be severe and destructive when accompanied by strong winds, particularly under [[Cumulonimbus cloud|cumulonimbus formation]].<ref>{{cite web|title= Strong dust storm in Delhi on May 30, 2014|url=https://in.news.yahoo.com/huge-dust-storm--heavy-rain-in-delhi--metro-suspended-123810015.html}}</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.

[[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 the humid season in Delhi. This season is marked by high levels of humidity and high heat. Day temperatures drop below {{convert|40|C|F}} as humidity suddenly soars.<ref>{{cite web|title= Weather in July in Delhi|url=http://weatherspark.com/averages/33934/7/New-Delhi-India}}</ref> July is marked by high heat and relatively less precipitation (as compared to August). 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>{{cite web|title= Weather in August in Delhi|url=http://weatherspark.com/averages/33934/8/New-Delhi-India}}</ref> By September, the amount and frequency of precipitation drops, though humidity remains high.<ref>{{cite web|title= Weather in September in Delhi|url=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.

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 {{convert|30|C|F}} by late October and there is a gradual fall in average temperature. Minimum temperature drops below {{convert|20|C|F}}.<ref>{{cite web|title= Weather in Delhi in November|url=http://weatherspark.com/averages/33934/11/New-Delhi-India}}</ref> During Autumn, the wind direction begins changing from South-Westerly to North-Westerly. Around late autumn/early winter, the variation between morning and afternoon temperatures in a day becomes considerable, and can often be more than {{convert|20|C|F}}, with minimum dropping to under {{convert|10|C|F}} and maximum still hovering slightly under {{convert|30|C|F}}. This season ends by early December.

Winter arrives in Delhi by early November. Minimum temperatures gradually enter single digits by this time of the year, while days are cool. 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 by [[Western Disturbance]], which bring cloud cover and  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 {{convert|0|C|F}},<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 very 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 {{convert|15|C|F}}. When the minimum temperature ventures very close to the {{convert|0|C|F}} 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 | archive-url=https://web.archive.org/web/20140109074912/http://articles.timesofindia.indiatimes.com/2006-01-09/delhi/27791060_1_snow-cold-waves-chilly-morning | url-status=dead | archive-date=2014-01-09 | work=[[The Times of India]] | title=When Delhi woke up to 'snow' | date=2006-01-09}}</ref> [[Snow]] is a practical impossibility for Delhi (and the rest of [[Indo-Gangetic Plain|Northern Plains]]) due to very dry nature of its winter- the coldest conditions happen under clear skies when icy winds rush in from the Himalayas, and a cloud cover (which is necessary for causing snowfall) rather warms the city by trapping heat, thereby junking any possibility of snow. Delhi's winter is marked by very dense [[fog]] and [[haze]], which dramatically reduce visibility<ref>{{cite web|title= An instance of dense fog in Delhi|url=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, cold north-westerly winds from the upper reaches of [[Himalayas]] blowing across the city makes the days feel colder, despite any sunshine and the nights further cold.<ref>{{cite web|title= Cold wave forces schools shut in Delhi|url=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>{{cite web|title= Cold wave, slight rise in temperature on January 20, 2011|url=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>{{cite web|title= Hailstorm in Delhi|url=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 {{convert|20|C|F}} and days become pleasant.

Temperature records for Delhi exist for a period of a little over 100 years. The lowest ever temperature reading during this period is {{convert|-2.2|C|F}}, recorded on 11 January 1967 at [[India Meteorological Department|Met]] Delhi Palam. And, the highest ever temperature reading during the same period is {{convert|48.4|C|F}} recorded on 26 May 1998, again at [[India Meteorological Department|Met]] Delhi Palam.<ref name="Indian Met Department, Pune"/><ref name="red">{{Cite web|url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf |title=Extremes for Delhi |publisher=Indian Meteorological Department |accessdate=21 January 2015 |url-status=dead |archiveurl=https://www.webcitation.org/6GmnoaB0m?url=http://www.imdpune.gov.in/Temp_Extremes/histext2010.pdf |archivedate=21 May 2013 }}</ref>

 

| May record high C = 48.4

|year record high C = 48.4

|year high C = 31.8

|year low C = 19.0

|year rain mm = 674.5

|year rain days = 35.7

|time day = 17:30 [[Indian Standard Time|IST]]

|year humidity = 45

|date=April 2014

|source 1 = India Meteorological Department<ref name=IMDnormals>

{{Reflist|2}}

[[Category:Climate of India]]