Chicago

===Climate===
{{main|Climate of Chicago}}
[[File:Steam Rising from Chicago River.jpg|thumb|upright|The Chicago River during the [[Early 2014 North American cold wave|January 2014 cold wave]]]]
The city lies within the typical hot-summer [[humid continental climate]] ([[Köppen climate classification|Köppen]]: ''Dfa''), and experiences four distinct seasons.<ref>{{Cite web |url=https://stateclimatologist.web.illinois.edu/climate-of-illinois/climate-of-chicago/ |title=Climate of Chicago – Illinois State Climatologist |language=en-US |access-date=March 24, 2020 |archive-date=March 24, 2020 |archive-url=https://web.archive.org/web/20200324165100/https://stateclimatologist.web.illinois.edu/climate-of-illinois/climate-of-chicago/ |url-status=live }}</ref><ref>{{Cite book |last1=Mölders |first1=Nicole |url=https://books.google.com/books?id=nWr1AwAAQBAJ&q=hot-summer+humid+continental+climate+CHICAGO&pg=PA521 |title=Lectures in Meteorology |last2=Kramm |first2=Gerhard |date=July 5, 2014 |publisher=Springer |isbn=978-3-319-02144-7 |language=en |access-date=November 9, 2020 |archive-date=July 9, 2023 |archive-url=https://web.archive.org/web/20230709112337/https://books.google.com/books?id=nWr1AwAAQBAJ&q=hot-summer+humid+continental+climate+CHICAGO&pg=PA521 |url-status=live }}</ref><ref>{{Cite web |url=http://www.weatherbase.com/weather/weather-summary.php3?s=3527&cityname=Chicago,+Illinois,+United+States+of+America |title=Chicago, Illinois Köppen Climate Classification (Weatherbase) |website=Weatherbase |access-date=March 24, 2020 |archive-date=May 19, 2020 |archive-url=https://web.archive.org/web/20200519043008/http://www.weatherbase.com/weather/weather-summary.php3?s=3527&cityname=Chicago,+Illinois,+United+States+of+America |url-status=live }}</ref> [[Summer]]s are hot and humid, with frequent [[heat waves]]. The July daily average temperature is {{convert|75.4|°F|1}}, with afternoon temperatures peaking at {{convert|84.5|°F|1}}. In a normal summer, temperatures reach at least {{convert|90|°F|0}} on 17&nbsp;days, with lakefront locations staying cooler when winds blow off the lake. [[Winter]]s are relatively cold and snowy. [[Blizzard]]s do occur, such as in [[January 31 – February 2, 2011 North American blizzard|winter 2011]].<ref>[https://www.chicagotribune.com/news/weather/chi-110201-monster-snowstorm-2011-pictures-photogallery.html Photos: The blizzard of 2011] {{Webarchive|url=https://web.archive.org/web/20190422210415/https://www.chicagotribune.com/news/weather/chi-110201-monster-snowstorm-2011-pictures-photogallery.html |date=April 22, 2019 }} ''Chicago Tribune''</ref> There are many sunny but cold days. The normal winter high from December through March is about {{convert|36|°F|0}}. January and February are the coldest months. A [[January–February 2019 North American cold wave|polar vortex in January 2019]] nearly broke the city's cold record of {{convert|-27|°F|0}}, which was set on January 20, 1985.<ref>[https://www.cnn.com/2019/01/31/weather/winter-weather-thursday-wxc/index.html Extreme cold in Midwest will finally begin to ease grasp] {{Webarchive|url=https://web.archive.org/web/20190131210531/https://www.cnn.com/2019/01/31/weather/winter-weather-thursday-wxc/index.html |date=January 31, 2019 }} [[CNN]], Holly Yan and Madeline Holcombe, January 31, 2019</ref><ref>[https://www.chicagotribune.com/news/weather/ct-met-viz-chicago-record-coldest-days-htmlstory.html At 23 below, Wednesday marked Chicago's 4th coldest temperature recorded] {{Webarchive|url=https://web.archive.org/web/20190423013906/https://www.chicagotribune.com/news/weather/ct-met-viz-chicago-record-coldest-days-htmlstory.html |date=April 23, 2019 }} ''Chicago Tribune'', Jonathon Berlin and Kori Rumore, January 31, 2019</ref><ref>[https://www.foxnews.com/us/university-of-iowa-student-dies-during-polar-vortex-7-other-deaths-linked-to-wintry-blast University of Iowa student dies during polar vortex; 7 other deaths linked to wintry blast] {{Webarchive|url=https://web.archive.org/web/20190131172237/https://www.foxnews.com/us/university-of-iowa-student-dies-during-polar-vortex-7-other-deaths-linked-to-wintry-blast |date=January 31, 2019 }} [[Fox News]], Stephen Sorace, January 31, 2019</ref> Measurable snowfall can continue through the first or second week of April.<ref>[https://www.nbcchicago.com/weather/weather-history-when-does-chicago-typically-see-its-final-snow-of-the-season/2804459/ Weather History: When Does Chicago Typically See Its Final Snow of the Season?] {{Webarchive|url=https://web.archive.org/web/20230313144928/https://www.nbcchicago.com/weather/weather-history-when-does-chicago-typically-see-its-final-snow-of-the-season/2804459/ |date=March 13, 2023 }} NBC, April 11, 2022</ref>

[[Spring (season)|Spring]] and [[autumn]] are mild, short seasons, typically with low humidity. [[Dew point]] temperatures in the summer range from an average of {{convert|55.8|°F|1}} in June to {{convert|61.7|°F|1}} in July.<ref name=NOAA/> They can reach nearly {{convert|80|°F}}, such as during the July 2019 heat wave. The city lies within [[United States Department of Agriculture|USDA]] plant [[hardiness zone]] 6a, transitioning to 5b in the suburbs.<ref>{{cite web |url=http://planthardiness.ars.usda.gov/PHZMWeb/ |title=USDA Plant Hardiness Zone Map |publisher=USDA/Agricultural Research Center, PRISM Climate Group Oregon State University |access-date = June 16, 2014 |url-status=dead |archive-url = https://web.archive.org/web/20140227032333/http://planthardiness.ars.usda.gov/PHZMWeb/ |archive-date = February 27, 2014}}</ref>

According to the [[National Weather Service]], Chicago's highest official temperature reading of {{convert|105|F|abbr=on}} was recorded on July 24, 1934.<!--AS MEASURED AT UCHICAGO, THE OFFICIAL REPORTING STATION AT THE TIME; THE 109F ON 1934-07-23 WAS AT MIDWAY--><ref name="temperature records">[http://www.crh.noaa.gov/lot/?n=chi_records Chicago's Official Records] {{Webarchive|url=https://web.archive.org/web/20121028054101/http://www.crh.noaa.gov/lot/?n=chi_records |date=October 28, 2012 }}. National Weather Service. Retrieved November 25, 2012.</ref> [[Chicago Midway International Airport|Midway Airport]] reached {{convert|109|°F|abbr=on}} one day prior and recorded a [[heat index]] of {{convert|125|°F|°C}} during the [[1995 Chicago heat wave|1995 heatwave]].<ref name="Chicago Top 20 of 20th century"/> The lowest official temperature of {{convert|-27|°F|0}} was recorded on [[January 1985 Arctic outbreak|January 20, 1985]], at O'Hare Airport.<ref name = NOAA/><ref name="Chicago Top 20 of 20th century"/> Most of the city's rainfall is brought by [[thunderstorm]]s, averaging 38 a year. The region is prone to [[severe thunderstorm]]s during the spring and summer which can produce large hail, damaging winds, and occasionally tornadoes.<ref>{{cite web |title=A Study of Chicago's Significant Tornadoes |url=http://www.crh.noaa.gov/lot/?n=Sigchitorn |work=[[National Weather Service]] |publisher=[[NOAA]] |access-date=May 10, 2013 |archive-date=November 5, 2013 |archive-url=https://web.archive.org/web/20131105160039/http://www.crh.noaa.gov/lot/?n=Sigchitorn |url-status=live }}</ref>

Like other major cities, Chicago experiences an [[urban heat island]], making the city and its suburbs milder than surrounding rural areas, especially at night and in winter. The proximity to Lake Michigan tends to keep the Chicago lakefront somewhat cooler in summer and less brutally cold in winter than inland parts of the city and suburbs away from the lake.<ref>{{cite web |url=http://www.epa.gov/heatisland/pilot/archives/Chicago.pdf |archive-url=https://web.archive.org/web/20081101090214/http://epa.gov/heatisland/pilot/archives/Chicago.pdf |archive-date=November 1, 2008 |url-status=live |title=Heat Island Effect |access-date=April 20, 2016}}</ref> Northeast winds from wintertime [[low-pressure area|cyclones]] departing south of the region sometimes bring the city [[lake-effect snow]].<ref>{{cite web |url=https://www.chicagotribune.com/news/weather/ct-wea-asktom-0307-20180306-column.html |title=Ask Tom: Does Chicago Get Lake-Effect Snow? |website=Chicago Tribune |access-date=January 6, 2018 |archive-date=March 7, 2018 |archive-url=https://web.archive.org/web/20180307034058/http://www.chicagotribune.com/news/weather/ct-wea-asktom-0307-20180306-column.html |url-status=live }}</ref>

{{Chicago weatherbox}}
{|style="width:100%;text-align:center;line-height:1.2em;margin-left:auto;margin-right:auto" class="wikitable mw-collapsible mw-collapsed"
|-
!Colspan=14|Sunshine data for Chicago
|-
!Month
!Jan
!Feb
!Mar
!Apr
!May
!Jun
!Jul
!Aug
!Sep
!Oct
!Nov
!Dec
!style="border-left-width:medium"|Year
|-
!Mean daily daylight hours
|style="background:#F0F011;color:#000000;"|10.0
|style="background:#F7F722;color:#000000;"|11.0
|style="background:#FFFF33;color:#000000;"|12.0
|style="background:#FFFF44;color:#000000;"|13.0
|style="background:#FFFF66;color:#000000;"|15.0
|style="background:#FFFF66;color:#000000;"|15.0
|style="background:#FFFF66;color:#000000;"|15.0
|style="background:#FFFF55;color:#000000;"|14.0
|style="background:#FFFF33;color:#000000;"|12.0
|style="background:#F7F722;color:#000000;"|11.0
|style="background:#F0F011;color:#000000;"|10.0
|style="background:#E9E900;color:#000000;"|9.0
|style="background:#FFFF35;color:#000000;border-left-width:medium"|12.2
|-
!Colspan=14 style="background:#f8f9fa;font-weight:normal;font-size:95%;"|Source: Weather Atlas<ref name="Weather Atlas">{{cite web |url=https://www.weather-us.com/en/illinois-usa/chicago-climate |title=Chicago, Illinois, USA – Monthly weather forecast and Climate data |publisher=Weather Atlas |access-date=February 7, 2019 |archive-date=April 15, 2019 |archive-url=https://web.archive.org/web/20190415040947/https://www.weather-us.com/en/illinois-usa/chicago-climate |url-status=live }}</ref>
|}