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Built 2026-10-19 (19 October 2026)

Nights at or above 25 C (77 F) in Chicago

Chicago has had nights with a minimum temperature at or above 25 C (77 F) in 34 years, most in 2012 with 9. Days per year, season span, streaks and every date.

Key Facts for Chicago

  • Chicago has had nights with a minimum temperature at or above 25 C (77 F) in 34 years, 84 days in all.
  • The most in one year was 9 days in 2012.
  • In 2026, the latest year on file, there were 5 such days.
  • The earliest first date in a year was 28 May 2012.
  • The latest last date in a year was 10 September 2013.
  • The longest run inside a single year was 4 days in 1972.
  • 2 years with under 90 percent of days observed are left out of these rankings.

Days per Year

34 years, 84 days
Nights at or above 25 C (77 F) per year in Chicago Days per year in Chicago with a minimum temperature at or above 25 C (77 F). The line is the decade average. The most was 9 in 2012. Grey bars are years with under 90 percent of days observed, left out of rankings. 0358101959: 11968: 31970: 21972: 51975: 11977: 61980: 11981: 11982: 11983: 11984: 11987: 11988: 61990: 11994: 21995: 41999: 32002: 12005: 12006: 32009: 12010: 12011: 22012: 92013: 32014: 12018: 32019: 12020: 32021: 12023: 12024: 32025: 52026: 51959198420092023
Days per year in Chicago with a minimum temperature at or above 25 C (77 F). The line is the decade average. The most was 9 in 2012. Grey bars are years with under 90 percent of days observed, left out of rankings.
Nights at or above 25 C (77 F) per year in Chicago
YearDaysDecade average
195911
196833
197023.5
197253.5
197513.5
197763.5
198011.7
198111.7
198211.7
198311.7
198411.7
198711.7
198861.7
199012.5
199422.5
199542.5
199932.5
200211.5
200511.5
200631.5
200911.5
201012.9
201122.9
201292.9
201332.9
201412.9
201832.9
201912.9
202033
202113
202313
202433
202553
202653

Season Span

earliest 28 May, latest 10 September
First to last qualifying date each year in Chicago For each year, a bar from the first to the last day in Chicago meeting 25 C (77 F). Long bars mean a long season. 1959: 28 June 1959 to 28 June 19591968: 6 August 1968 to 23 August 19681970: 30 June 1970 to 2 July 19701972: 20 July 1972 to 17 August 19721975: 24 August 1975 to 24 August 19751977: 4 July 1977 to 27 August 19771980: 15 July 1980 to 15 July 19801981: 8 July 1981 to 8 July 19811982: 17 July 1982 to 17 July 19821983: 28 July 1983 to 28 July 19831984: 17 June 1984 to 17 June 19841987: 1 August 1987 to 1 August 19871988: 1 August 1988 to 17 August 19881990: 4 July 1990 to 4 July 19901994: 15 June 1994 to 5 July 19941995: 13 July 1995 to 14 August 19951999: 4 July 1999 to 30 July 19992002: 21 July 2002 to 21 July 20022005: 24 July 2005 to 24 July 20052006: 30 July 2006 to 2 August 20062009: 9 August 2009 to 9 August 20092010: 5 July 2010 to 5 July 20102011: 18 July 2011 to 19 July 20112012: 28 May 2012 to 23 July 20122013: 18 July 2013 to 10 September 20132014: 17 June 2014 to 17 June 20142018: 17 June 2018 to 27 August 20182019: 19 July 2019 to 19 July 20192020: 18 July 2020 to 28 August 20202021: 6 July 2021 to 6 July 20212023: 23 August 2023 to 23 August 20232024: 17 June 2024 to 26 August 20242025: 21 June 2025 to 10 August 20252026: 30 June 2026 to 3 September 20261959197719841995200920142023JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day in Chicago meeting 25 C (77 F). Long bars mean a long season.
First to last qualifying date each year in Chicago
YearFirst dateLast date
19591959-06-281959-06-28
19681968-08-061968-08-23
19701970-06-301970-07-02
19721972-07-201972-08-17
19751975-08-241975-08-24
19771977-07-041977-08-27
19801980-07-151980-07-15
19811981-07-081981-07-08
19821982-07-171982-07-17
19831983-07-281983-07-28
19841984-06-171984-06-17
19871987-08-011987-08-01
19881988-08-011988-08-17
19901990-07-041990-07-04
19941994-06-151994-07-05
19951995-07-131995-08-14
19991999-07-041999-07-30
20022002-07-212002-07-21
20052005-07-242005-07-24
20062006-07-302006-08-02
20092009-08-092009-08-09
20102010-07-052010-07-05
20112011-07-182011-07-19
20122012-05-282012-07-23
20132013-07-182013-09-10
20142014-06-172014-06-17
20182018-06-172018-08-27
20192019-07-192019-07-19
20202020-07-182020-08-28
20212021-07-062021-07-06
20232023-08-232023-08-23
20242024-06-172024-08-26
20252025-06-212025-08-10
20262026-06-302026-09-03

Every Year

Nights at or above 25 C (77 F) per year in Chicago
YearDaysFirst dateLast dateLongest streak in yearCoverage
2026530 June 20263 September 20263 daysIncomplete, not ranked
2025521 June 202510 August 20253 daysComplete
2024317 June 202426 August 20242 daysComplete
2023123 August 202323 August 20231 daysComplete
202116 July 20216 July 20211 daysComplete
2020318 July 202028 August 20202 daysComplete
2019119 July 201919 July 20191 daysComplete
2018317 June 201827 August 20181 daysComplete
2014117 June 201417 June 20141 daysComplete
2013318 July 201310 September 20131 daysComplete
2012928 May 201223 July 20124 daysComplete
2011218 July 201119 July 20112 daysComplete
201015 July 20105 July 20101 daysComplete
200919 August 20099 August 20091 daysComplete
2006330 July 20062 August 20062 daysComplete
2005124 July 200524 July 20051 daysComplete
2002121 July 200221 July 20021 daysComplete
199934 July 199930 July 19992 daysComplete
1995413 July 199514 August 19952 daysComplete
1994215 June 19945 July 19941 daysComplete
199014 July 19904 July 19901 daysComplete
198861 August 198817 August 19884 daysComplete
198711 August 19871 August 19871 daysComplete
1984117 June 198417 June 19841 daysComplete
1983128 July 198328 July 19831 daysComplete
1982117 July 198217 July 19821 daysComplete
198118 July 19818 July 19811 daysComplete
1980115 July 198015 July 19801 daysComplete
197764 July 197727 August 19773 daysComplete
1975124 August 197524 August 19751 daysComplete
1972520 July 197217 August 19724 daysComplete
1970230 June 19702 July 19701 daysComplete
196836 August 196823 August 19681 daysComplete
1959128 June 195928 June 19591 daysComplete
Decade averages for Nights at or above 25 C (77 F) in Chicago
DecadeAverage days per yearYears counted
1950s1.01
1960s3.01
1970s3.54
1980s1.77
1990s2.54
2000s1.54
2010s2.97
2020s2.65

Compare with your own threshold in the threshold explorer. Fahrenheit thresholds are converted to tenths of a degree Celsius once, rounding half up.

Download the Data

  • Data for Nights at or above 25 C (77 F) in Chicago, by year: CSV or JSON. Field meanings are on the data page.

Source: NOAA National Centers for Environmental Information, Global Historical Climatology Network Daily (GHCN-Daily). Records are computed by World Extreme Weather Monitor and are not official NOAA products. (US Government open data (NOAA NCEI)) Data as of 2026-10-17 (17 October 2026). Threshold counts are computed by this site from the threaded city record.

Data as of . Last revised (2026-10-17).