London

===Climate===
{{main|Climate of London}}
London has a temperate [[oceanic climate]] ([[Köppen climate classification|Köppen]]: ''Cfb''). Rainfall records have been kept in the city since at least 1697, when records began at [[Kew]]. At Kew, the most rainfall in one month is {{Convert|189|mm|in|order=flip|abbr=}} in November 1755 and the least is {{Convert|0|mm|in|order=flip|abbr=}} in both December 1788 and July 1800. Mile End also had {{Convert|0|mm|in|order=flip|abbr=}} in April 1893.<ref>{{Cite web |url=https://www.trevorharley.com/weather-april.html |title=Weather April |website=trevorharley.com}}</ref> The wettest year on record is 1903, with a total fall of {{Convert|969|mm|in|order=flip|abbr=}} and the driest is 1921, with a total fall of {{Convert|308|mm|in|order=flip|abbr=}}.<ref>{{Cite web |url=http://old.wetterzentrale.de/klima/pkewgar.html |title=Niederschlagsmonatssummen KEW GARDENS 1697–1987 |access-date=16 May 2020 |archive-date=24 February 2021 |archive-url=https://web.archive.org/web/20210224100657/http://old.wetterzentrale.de/klima/pkewgar.html |url-status=dead }}</ref> The average annual precipitation amounts to about 600&nbsp;mm, which is half the annual rainfall of [[New York City]].<ref>{{Cite web |title=Average Annual Precipitation by City in the US – Current Results |url=https://www.currentresults.com/Weather/US/average-annual-precipitation-by-city.php|access-date=25 March 2021 |website=currentresults.com}}</ref> Despite relatively low annual precipitation, London receives 109.6 rainy days on the 1.0&nbsp;mm threshold annually. London is vulnerable to [[climate change in the United Kingdom|climate change]], and there is concern among [[hydrology|hydrological]] experts that households may run out of water before 2050.<ref>{{cite news|url=https://www.independent.co.uk/climate-change/news/london-water-drought-climate-change-b2079811.html?amp|title=London could run out of water in 25 years as cities worldwide face rising risk of drought, report warns|author=Saphora Smith|newspaper=The Independent|date=16 May 2022|access-date=5 June 2022}}</ref>

Temperature extremes in London range from {{convert|40.2|°C|°F|1}} at Heathrow on 19 July 2022 down to {{convert|-17.4|°C|°F}} at Northolt on 13 December 1981.<ref>{{Cite web |url=http://starlingsroost.ddns.net/weather/ukobs/mintemp_map.php?date=1981-12-13 |title=Minimum Temperatures observed on 13th Dec 1981 at 06Z (SYNOP)/09Z (MIDAS/BUFR) UTC (529 reports)|access-date=30 April 2023}}</ref><ref>{{Cite web |url=https://www.ncdc.noaa.gov/cdo-web/search |title=Search &#124; Climate Data Online (CDO) &#124; National Climatic Data Center (NCDC) |access-date=1 August 2019 |archive-url=https://web.archive.org/web/20190729134639/https://www.ncdc.noaa.gov/cdo-web/search |archive-date=29 July 2019 |url-status=dead}}</ref> Records for [[atmospheric pressure]] have been kept at London since 1692. The highest pressure ever reported is {{convert|1049.8|mbar|inHg}} on 20 January 2020.<ref>{{Cite news |last=Amos |first=Jonathan |url=https://www.bbc.com/news/science-environment-51180211 |title=London breaks a high-pressure record |date=20 January 2020 |work=BBC News |access-date=13 February 2020}}</ref>

Summers are generally warm, sometimes hot. London's average July high is 23.5&nbsp;°C (74.3&nbsp;°F). On average each year, London experiences 31 days above {{convert|25|°C|°F|1}} and 4.2 days above {{convert|30.0|°C|°F|1}}. During the [[2003 European heat wave]], prolonged heat led to hundreds of heat-related deaths.<ref>{{Cite journal |title=The impact of the 2003 heat wave on daily mortality in England and Wales and the use of rapid weekly mortality estimates |journal=Eurosurveillance |volume=10 |issue=7 |date=1 July 2005 |first1=H |last1=Johnson |first2=RS |last2=Kovats |first3=G |last3=McGregor |first4=J |last4=Stedman |first5=M |last5=Gibbs |first6=H |last6=Walton |pages=15–16 |doi=10.2807/esm.10.07.00558-en |pmid=16088043 |url=http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=558|doi-access=free}}</ref> A previous spell of 15 consecutive days above {{convert|32.2|°C|°F|1}} in England in 1976 also caused many heat related deaths.<ref>{{Cite web |last=Taylor |first=Brian |year=2002 |title=1976. The Incredible Heatwave. |url=https://www.theweatheroutlook.com/twoother/twocontent.aspx?type=libgen&id=1432 |url-status=live|archive-url=https://web.archive.org/web/20080712080114/https://www.theweatheroutlook.com/twoother/twocontent.aspx?type=libgen&id=1432 |archive-date=12 July 2008 |access-date=25 March 2021 |website=TheWeatherOutlook}}</ref> A previous temperature of {{convert|37.8|°C|°F}} in August 1911 at the Greenwich station was later disregarded as non-standard.<ref name="metoffice.gov.uk">{{Cite web |year=1911 |title=Monthly Weather Report of the Meteorological Office |url=https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/i/7/aug1911.pdf |url-status=dead |archive-url=https://web.archive.org/web/20171113123406/https://www.metoffice.gov.uk/binaries/content/assets/mohippo/pdf/i/7/aug1911.pdf |archive-date=13 November 2017 |access-date=25 March 2021 |publisher=Wyman and Sons, Ltd.}}</ref> Droughts can also, occasionally, be a problem, especially in summer, most recently in summer 2018, and with much drier than average conditions prevailing from May to December.<ref>{{Cite web |year=2018 |title=UK Droughts: SPI |url=https://eip.ceh.ac.uk/apps/droughts/ |access-date=25 March 2021 |website=[[UK Centre for Ecology & Hydrology]]}}</ref> However, the most consecutive days without rain was 73 days in the spring of 1893.<ref>{{Cite web |url=https://www.weatheronline.co.uk/reports/philip-eden/Longest-drought-for-2-years.htm |title=Philip Eden: Longest drought for 2 years – weatheronline.co.uk |website=weatheronline.co.uk |access-date=10 April 2019}}</ref>

Winters are generally cool with little temperature variation. Heavy snow is rare but snow usually falls at least once each winter. Spring and autumn can be pleasant. As a large city, London has a considerable [[urban heat island]] effect,<ref>{{Cite web |url=http://legacy.london.gov.uk/mayor/environment/climate-change/docs/UHI_summary_report.pdf |title=London's Urban Heat Island: A Summary for Decision Makers |publisher=Greater London Authority |date=October 2006 |access-date=29 April 2015 |url-status=dead |archive-url=https://web.archive.org/web/20120816015955/http://legacy.london.gov.uk/mayor/environment/climate-change/docs/UHI_summary_report.pdf |archive-date=16 August 2012}}</ref> making the centre of London at times {{convert|5|C-change|0}} warmer than the suburbs and outskirts.<ref>{{Cite news |last=Eden |first=Philip |date=9 June 2004 |title=Ever Warmer as Temperatures Rival France |location=London |url=https://www.telegraph.co.uk/news/uknews/1463994/Ever-warmer-as-temperatures-rival-France.html |url-status=live |access-date=25 March 2021 |archive-url=https://web.archive.org/web/20200326104750/https://www.telegraph.co.uk/news/uknews/1463994/Ever-warmer-as-temperatures-rival-France.html |archive-date=26 March 2020}}</ref>

{{London weatherbox}}