Daily records
Page built 2026-10-19
Data as of 2026-10-17
Search
Built 2026-10-19 (19 October 2026)

Days at or above 100 F (37.8 C) in Chicago

Chicago has had days with a maximum temperature at or above 100 F (37.8 C) in 10 years, most in 1988 with 7. Days per year, season span, streaks and every date.

Key Facts for Chicago

  • Chicago has had days with a maximum temperature at or above 100 F (37.8 C) in 10 years, 23 days in all.
  • The most in one year was 7 days in 1988.
  • In 2023, the latest year on file, there were 1 such days.
  • The earliest first date in a year was 20 June 1988.
  • The latest last date in a year was 24 August 2023.
  • The longest run inside a single year was 3 days in 2012.
  • 2 years with under 90 percent of days observed are left out of these rankings.

Days per Year

10 years, 23 days
Days at or above 100 F (37.8 C) per year in Chicago Days per year in Chicago with a maximum temperature at or above 100 F (37.8 C). The line is the decade average. The most was 7 in 1988. Grey bars are years with under 90 percent of days observed, left out of rankings. 024681980: 21983: 21988: 71989: 11991: 21995: 21999: 12005: 12012: 42023: 11980
Days per year in Chicago with a maximum temperature at or above 100 F (37.8 C). The line is the decade average. The most was 7 in 1988. Grey bars are years with under 90 percent of days observed, left out of rankings.
Days at or above 100 F (37.8 C) per year in Chicago
YearDaysDecade average
198023
198323
198873
198913
199121.7
199521.7
199911.7
200511
201244
202311

Season Span

earliest 20 June, latest 24 August
First to last qualifying date each year in Chicago For each year, a bar from the first to the last day in Chicago meeting 100 F (37.8 C). Long bars mean a long season. 1980: 7 July 1980 to 20 July 19801983: 22 July 1983 to 28 July 19831988: 20 June 1988 to 2 August 19881989: 10 July 1989 to 10 July 19891991: 22 July 1991 to 2 August 19911995: 13 July 1995 to 14 July 19951999: 30 July 1999 to 30 July 19992005: 24 July 2005 to 24 July 20052012: 28 June 2012 to 6 July 20122023: 24 August 2023 to 24 August 202319801988199119992012JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day in Chicago meeting 100 F (37.8 C). Long bars mean a long season.
First to last qualifying date each year in Chicago
YearFirst dateLast date
19801980-07-071980-07-20
19831983-07-221983-07-28
19881988-06-201988-08-02
19891989-07-101989-07-10
19911991-07-221991-08-02
19951995-07-131995-07-14
19991999-07-301999-07-30
20052005-07-242005-07-24
20122012-06-282012-07-06
20232023-08-242023-08-24

Every Year

Days at or above 100 F (37.8 C) per year in Chicago
YearDaysFirst dateLast dateLongest streak in yearCoverage
2023124 August 202324 August 20231 daysComplete
2012428 June 20126 July 20123 daysComplete
2005124 July 200524 July 20051 daysComplete
1999130 July 199930 July 19991 daysComplete
1995213 July 199514 July 19952 daysComplete
1991222 July 19912 August 19911 daysComplete
1989110 July 198910 July 19891 daysComplete
1988720 June 19882 August 19882 daysComplete
1983222 July 198328 July 19831 daysComplete
198027 July 198020 July 19801 daysComplete
Decade averages for Days at or above 100 F (37.8 C) in Chicago
DecadeAverage days per yearYears counted
1980s3.04
1990s1.73
2000s1.01
2010s4.01
2020s1.01

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 Days at or above 100 F (37.8 C) 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).