Chicago, IL

Illinois · Records since 1872–2026

☀️ 77°F
Currently in Chicago
As of 1:00 PM CDT

Records for September 7

🔥 Record High

100°F

September 7, 1960

+21° from 79° normal

❄ Record Low

42°F

September 7, 1986

-18° from 60° normal
🌞 Normal high: 79°F 🌑 Normal low: 60°F 1991–2020 normals

All-Time Records — Chicago

🔥
105°F
Hottest Day Ever
Jul 24, 1934
❄
-27°F
Coldest Day Ever
Jan 20, 1985
🌧
6.86"
Wettest Day Ever
Jul 23, 2011
☃
18.6"
Most Snow in One Day
Jan 2, 1999

Top 10 Record Highs — September 7

# Temp Date
🏆 100°F September 7, 1960
2 100°F September 7, 1939
3 99°F September 7, 1985
4 96°F September 7, 1959
5 95°F September 7, 1945
6 95°F September 7, 1899
7 94°F September 7, 1964
8 93°F September 7, 1913
9 92°F September 7, 1922
10 91°F September 7, 1978

Top 5 Record Lows — September 7

# Temp Date
🥶 42°F September 7, 1986
2 44°F September 7, 1988
3 47°F September 7, 2025
4 47°F September 7, 1956
5 48°F September 7, 2024
About this data — Records are sourced from the NOAA Threadex dataset via RCC ACIS, a quality-controlled record for long-term climate stations. Threadex adjusts for station relocations and observation-time changes, making records comparable across all years since 1872–2026. Climate normals represent the 1991–2020 average.

Heat Wave Summary — Chicago

threshold: 91°F (90th percentile of historical Jun–Aug highs)
3.9
Avg heat wave length
days (historical)
96°
Avg peak temp
during heat waves
30
Dangerous nights 2026
Overnights ≥ 70°F
3
Heat waves 2026
so far

2026 Daily High Temperature vs Normal

Year to date
Above normal Below normal

126 of 249 days with data were above the 1991–2020 normal high for their date.

Days ≥ 90°F Per Year

1872–2026
16
2026 so far
16
Avg/year 1970–2025
21
Avg/year (last 10 complete)
47
Most in a year (1988)

Average Daily High by Decade

Full year · complete decades only

Longest Heat Waves — Chicago

# Dates Days Peak Avg High Avg Overnight Low
🏆 Aug 25, 1953 – Sep 3, 1953 10 101°F (Sep 1) 98°F 71°F
2 Jul 26, 1955 – Aug 4, 1955 10 100°F (Jul 27) 96°F 76°F
3 Aug 19, 1959 – Aug 28, 1959 10 96°F (Aug 21) 94°F 74°F
4 Jul 27, 1988 – Aug 4, 1988 9 100°F (Aug 1) 97°F 72°F
5 Jul 17, 1987 – Jul 25, 1987 9 96°F (Jul 20) 93°F 71°F
6 Jun 30, 2012 – Jul 7, 2012 8 103°F (Jul 5) 98°F 75°F
7 Aug 17, 1947 – Aug 24, 1947 8 100°F (Aug 24) 97°F 74°F
8 Aug 22, 1948 – Aug 29, 1948 8 98°F (Aug 24) 95°F 72°F
9 May 16, 1977 – May 23, 1977 8 95°F (May 20) 92°F 70°F
10 Aug 4, 1900 – Aug 11, 1900 8 94°F (Aug 4) 93°F 75°F

Heat Waves Per Year

Warm Summer Nights (Jun–Aug)

Nights where the overnight low exceeded the 1991–2020 normal low

52
2026 total
above-normal nights
35.8
Avg / summer
1970–2020
72
Most in a summer
1921

Above-Normal Summer Nights Per Year

Average June–August Low by Decade

Overnight lows · complete decades only

Precipitation

Actual vs. 1991–2020 full-month and full-season normals

30.97"
2026 YTD
Normal: 27.41"
+3.56"
0.00"
September so far
September normal: 3.19"
-3.19"
10
2026 heavy rain days
Days with ≥ 1.0"

2026 Accumulation vs. Normal

Running total since Jan 1 against the normal pace for the same date · Chicago is 3.56" ahead of the normal pace

Monthly Precipitation — Last 24 Months

Blue = actual · dashed line = monthly normal

Annual Precipitation Per Year (1871–2026)

Blue = above average · tan = below average · gold = 2026 (partial)
Since 1871, annual totals have trended +0.37" per decade, about +5.6" across the record.

Heavy Rain Days Per Year (≥ 1.0")

Compare year-to-year changes in days with heavy rainfall (≥ 1.0")

Month in Review — August 2026

74.2°F

Average temperature · August 2026

119th-warmest month on record

40th-warmest August of 155 on record

+1.3° vs. 73.0° average (1991–2020)
81.3°F
Warmest month ever
July 1955
80.2°F
Warmest August ever
1947
96°F
Hottest of 2026
Jul 14

Average August Temperature by Year

1872–2026 · 2026 highlighted · trend +0.16° per decade (warming since 1872)

Precipitation — August 2026

Month total against the 1991–2020 average and every other August on record

5.02"
Total precipitation
August 2026
+0.78"
vs. average
Normal: 4.24" · 118% of normal
34th-wettest
August rank
of 156 on record
17.10"
Wettest August ever
1987 · driest 0.18" (1893)

August Precipitation by Year

1871–2026 · 2026 highlighted · trend +0.11" per decade (wetter since 1871)

Wettest Augusts on Record

# Year Total
1 1987 17.10"
2 2001 12.25"
3 1885 11.28"
4 2007 9.70"
5 1977 9.68"
6 1979 8.64"
7 1980 8.54"
8 1924 8.12"
9 2002 8.06"
10 1923 7.76"

Driest Augusts on Record

# Year Total
1 1893 0.18"
2 1889 0.39"
3 1879 0.45"
4 1881 0.54"
5 1894 0.60"
6 2020 0.80"
7 1976 0.80"
8 1973 0.85"
9 1962 0.85"
10 1974 0.90"

Warmest Augusts on Record

# Year Avg Temp
1 1947 80.2°F
2 1995 79.0°F
3 1955 78.7°F
4 1959 78.7°F
5 1983 77.3°F
6 2021 77.2°F
7 1988 76.8°F
8 2020 76.8°F
9 2010 76.7°F
10 1973 76.6°F

Warmest Months on Record (Any Month)

# Month Avg Temp
1 July 1955 81.3°F
2 July 1921 81.2°F
3 July 2012 81.0°F
4 August 1947 80.2°F
5 July 2020 79.2°F
6 July 2011 79.1°F
7 August 1995 79.0°F
8 August 1955 78.7°F
9 August 1959 78.7°F
10 July 1916 78.5°F

Nearby Stations — August 2026

How the same month ranked at the closest reporting stations

Station Avg Temp August Rank
Chicago, IL 74.2°F 40th of 155
South Bend, IN 71.7°F 62nd of 131
Rockford, IL 71.7°F 67th of 127
Milwaukee, WI 71.7°F 45th of 156
Holland, MI 70.3°F 58th of 117
About this data. Monthly averages are the mean of daily average temperatures, computed from NOAA Threadex records via RCC ACIS. Months missing more than three days of observations are excluded from the rankings, so the in-progress month never appears. Rankings cover 1,850 complete months on record. Precipitation totals sum the daily reports for the month, with trace amounts counted as zero. A month missing any day of precipitation data is left out entirely (an unreported day is unreported rain), so the precipitation ranking covers 156 complete Augusts. Normals are the 1991–2020 mean for the same calendar month. Trend lines are a least-squares fit across every year shown.

Fall in Review — Fall 2026

September 1 – November 30, 2026

Fall 2026 is still under way. Season totals and rankings appear once November closes; the markers below update as they happen.

Summer to Winter — 2026

Each turning point of the season against its 1991–2020 normal date, with the earliest and latest on record

Marker 2026 Normal vs. normal Earliest Latest Drift
Last 90°F day
The final day of summer heat
 Sep 4
so far
 Sep 1 Jul 1, 1967 Oct 6, 1963 +0.8 d/decade
Last 80°F day
The last genuinely warm afternoon
 Sep 5
so far
 Oct 5 Aug 31, 1876 Nov 1, 1950 +0.7 d/decade
First high below 50°F
The first afternoon that stays cold
 not yet Oct 21 Sep 21, 1913 Nov 20, 2024 +0.7 d/decade
First 32°F freeze
Growing season over
 not yet Oct 20 Sep 22, 1995 Nov 24, 1931 -0.5 d/decade
First 28°F hard freeze
Cold enough to end tender growth
 not yet Nov 3 Oct 2, 1974 Dec 3, 1899 -0.1 d/decade
First 20°F night
Winter cold arriving
 not yet Nov 24 Oct 18, 1948 Dec 31, 1923 +0.1 d/decade
First measurable snow
0.1" or more in a day
 not yet Nov 19 Oct 12, 2006 Dec 28, 2021 +0.1 d/decade

Drift is a least-squares fit across every year on record. Positive means the marker has been arriving later.

First Freeze by Year

The first 32°F night of each autumn since 1872 · trending -0.5 days earlier per decade

180
Normal length
1991–2020 average
235
Longest on record
1931
142
Shortest on record
1981

Growing Season Length by Year

Days between the last spring freeze and the first fall freeze · trending -1.1 days shorter per decade

Fall Average Temperature by Year

1872–2025 · 2026 highlighted · trend +0.07° per decade (warming since 1872)

Fall Precipitation by Year

1871–2025 · 2026 highlighted · trend +0.05" per decade (wetter since 1871)

About this data. Fall is meteorological autumn, September 1 through November 30, the window NOAA uses for seasonal statistics. Seasonal temperature is the day-weighted mean of the three monthly means; precipitation is their sum, and a season missing any of the three months is left out of the rankings. Freeze, heat and snow markers come from daily NOAA Threadex observations via RCC ACIS: freezes and snow are the first occurrence on or after July 1, and the last 90°F and 80°F days are the final ones anywhere in the calendar year. Growing season counts the freeze-free days between the last spring 32°F and the first fall 32°F.
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