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Built 2026-10-19 (19 October 2026)

Days with 100 mm (3.94 in) or more of precipitation in Chicago

Chicago has had days with 100 mm (3.94 in) or more of precipitation in 9 years, most in 1969 with 1. Days per year, season span, streaks and every date.

Key Facts for Chicago

  • Chicago has had days with 100 mm (3.94 in) or more of precipitation in 9 years, 9 days in all.
  • The most in one year was 1 days in 1969.
  • In 2017, the latest year on file, there were 1 such days.
  • The earliest first date in a year was 19 June 2009.
  • The latest last date in a year was 2 December 1982.
  • 2 years with under 90 percent of days observed are left out of these rankings.

Days per Year

9 years, 9 days
Days with 100 mm (3.94 in) or more of precipitation per year in Chicago Days per year in Chicago with 100 mm (3.94 in) or more of precipitation. The line is the decade average. The most was 1 in 1969. Grey bars are years with under 90 percent of days observed, left out of rankings. 001111969: 11982: 11987: 12001: 12002: 12008: 12009: 12011: 12017: 11969
Days per year in Chicago with 100 mm (3.94 in) or more of precipitation. The line is the decade average. The most was 1 in 1969. Grey bars are years with under 90 percent of days observed, left out of rankings.
Days with 100 mm (3.94 in) or more of precipitation per year in Chicago
YearDaysDecade average
196911
198211
198711
200111
200211
200811
200911
201111
201711

Season Span

earliest 19 June, latest 2 December
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 mm (3.94 in). Long bars mean a long season. 1969: 10 October 1969 to 10 October 19691982: 2 December 1982 to 2 December 19821987: 14 August 1987 to 14 August 19872001: 30 August 2001 to 30 August 20012002: 22 August 2002 to 22 August 20022008: 13 September 2008 to 13 September 20082009: 19 June 2009 to 19 June 20092011: 23 July 2011 to 23 July 20112017: 14 October 2017 to 14 October 201719691987200220092017JanFebMarAprMayJunJulAugSepOctNovDec
For each year, a bar from the first to the last day in Chicago meeting 100 mm (3.94 in). Long bars mean a long season.
First to last qualifying date each year in Chicago
YearFirst dateLast date
19691969-10-101969-10-10
19821982-12-021982-12-02
19871987-08-141987-08-14
20012001-08-302001-08-30
20022002-08-222002-08-22
20082008-09-132008-09-13
20092009-06-192009-06-19
20112011-07-232011-07-23
20172017-10-142017-10-14

Every Year

Days with 100 mm (3.94 in) or more of precipitation per year in Chicago
YearDaysFirst dateLast dateLongest streak in yearCoverage
2017114 October 201714 October 20171 daysComplete
2011123 July 201123 July 20111 daysComplete
2009119 June 200919 June 20091 daysComplete
2008113 September 200813 September 20081 daysComplete
2002122 August 200222 August 20021 daysComplete
2001130 August 200130 August 20011 daysComplete
1987114 August 198714 August 19871 daysComplete
198212 December 19822 December 19821 daysComplete
1969110 October 196910 October 19691 daysComplete
Decade averages for Days with 100 mm (3.94 in) or more of precipitation in Chicago
DecadeAverage days per yearYears counted
1960s1.01
1980s1.02
2000s1.04
2010s1.02

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 with 100 mm (3.94 in) or more of precipitation 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).