Chicago · United States

Chicago in September: every year compared

In September, Chicago averages highs of 23.1 °C and lows of 14.7 °C, with 75 mm of precipitation. The warmest September was 2005 (21.3 °C), the coldest 1949 (15.7 °C).

Avg. highAvg. high 23.1 °C

Avg. lowAvg. low 14.7 °C

PrecipitationPrecipitation 75 mm

Rainy daysRainy days 9

Day by day through September

Normal high and low for each day of September in Chicago.

Normal high and low, day by dayNormal 1991–2020

Every September in Chicago, ranked

86 months of September since 1940. The last one, 2025, ranks 23 of 86 (+0.7 °C vs normal).

194019832025

2025 · 19.6 °C · +0.7 °C vs normal · rank 23 of 86

Warmest years

1200521.3 °C
2197820.8 °C
3201620.8 °C
4201920.7 °C
5202120.7 °C

Coldest years

1194915.7 °C
2197516.0 °C
3199316.1 °C
4194316.1 °C
5197416.2 °C

All 86 years in a table

Year	Mean temperature	Daytime highs	Night lows	Precipitation	Hot days (30 °C+)	Rainy days
2025	19.6 °C	24.5 °C	15.0 °C	32 mm	0 days	6 days
2024	20.2 °C	25.0 °C	15.5 °C	53 mm	2 days	6 days
2023	19.9 °C	23.7 °C	16.3 °C	89 mm	3 days	12 days
2022	19.2 °C	23.0 °C	15.2 °C	68 mm	0 days	7 days
2021	20.7 °C	25.4 °C	16.3 °C	56 mm	1 day	9 days
2020	18.2 °C	22.3 °C	14.3 °C	113 mm	0 days	9 days
2019	20.7 °C	24.4 °C	17.2 °C	119 mm	1 day	15 days
2018	20.2 °C	24.1 °C	16.2 °C	56 mm	5 days	11 days
2017	19.8 °C	24.4 °C	15.4 °C	31 mm	7 days	5 days
2016	20.8 °C	24.5 °C	17.4 °C	70 mm	3 days	14 days
2015	20.2 °C	24.2 °C	16.1 °C	81 mm	5 days	7 days
2014	17.4 °C	21.9 °C	13.1 °C	74 mm	1 day	7 days
2013	19.7 °C	24.3 °C	15.1 °C	29 mm	4 days	6 days
2012	18.0 °C	22.5 °C	13.6 °C	50 mm	0 days	10 days
2011	17.3 °C	20.6 °C	13.9 °C	119 mm	3 days	17 days
2010	18.8 °C	22.9 °C	14.9 °C	104 mm	1 day	10 days
2009	18.8 °C	22.4 °C	15.0 °C	27 mm	0 days	6 days
2008	19.3 °C	23.4 °C	15.2 °C	225 mm	2 days	9 days
2007	20.5 °C	25.5 °C	15.5 °C	31 mm	4 days	6 days
2006	17.3 °C	20.9 °C	13.6 °C	141 mm	0 days	11 days
2005	21.3 °C	26.1 °C	16.6 °C	69 mm	6 days	10 days
2004	19.9 °C	24.7 °C	15.1 °C	14 mm	0 days	4 days
2003	17.9 °C	22.1 °C	13.5 °C	60 mm	0 days	6 days
2002	20.3 °C	25.1 °C	15.3 °C	38 mm	3 days	6 days
2001	17.4 °C	21.2 °C	13.2 °C	88 mm	0 days	11 days
2000	18.6 °C	23.1 °C	14.4 °C	47 mm	3 days	8 days
1999	18.1 °C	23.2 °C	12.8 °C	50 mm	4 days	4 days
1998	20.6 °C	25.0 °C	16.2 °C	40 mm	3 days	8 days
1997	18.5 °C	22.6 °C	14.5 °C	47 mm	0 days	9 days
1996	18.1 °C	22.0 °C	14.2 °C	88 mm	0 days	8 days
1995	17.8 °C	22.3 °C	13.2 °C	34 mm	1 day	6 days
1994	19.3 °C	23.6 °C	15.3 °C	57 mm	2 days	10 days
1993	16.1 °C	19.5 °C	12.7 °C	163 mm	0 days	15 days
1992	17.7 °C	21.8 °C	13.6 °C	132 mm	0 days	10 days
1991	18.3 °C	23.1 °C	13.8 °C	53 mm	4 days	8 days
1990	19.2 °C	23.2 °C	15.5 °C	44 mm	3 days	7 days
1989	17.3 °C	21.6 °C	13.1 °C	100 mm	0 days	9 days
1988	19.1 °C	24.0 °C	14.6 °C	73 mm	1 day	9 days
1987	18.4 °C	22.8 °C	14.6 °C	102 mm	0 days	12 days
1986	19.6 °C	23.7 °C	16.0 °C	130 mm	0 days	12 days
1985	19.3 °C	23.5 °C	15.5 °C	60 mm	2 days	11 days
1984	17.7 °C	22.0 °C	13.5 °C	107 mm	1 day	15 days
1983	19.1 °C	24.0 °C	14.4 °C	90 mm	6 days	11 days
1982	18.1 °C	22.6 °C	14.1 °C	57 mm	0 days	9 days
1981	17.6 °C	21.7 °C	14.0 °C	70 mm	0 days	12 days
1980	19.0 °C	23.6 °C	14.8 °C	105 mm	0 days	13 days
1979	18.8 °C	23.6 °C	14.1 °C	6 mm	0 days	3 days
1978	20.8 °C	25.5 °C	16.2 °C	92 mm	7 days	9 days
1977	18.6 °C	22.1 °C	15.4 °C	144 mm	0 days	12 days
1976	17.3 °C	22.3 °C	12.4 °C	64 mm	1 day	6 days
1975	16.0 °C	19.9 °C	12.0 °C	36 mm	0 days	5 days
1974	16.2 °C	21.0 °C	12.0 °C	52 mm	0 days	9 days
1973	19.4 °C	23.2 °C	15.9 °C	150 mm	3 days	13 days
1972	18.5 °C	22.2 °C	15.0 °C	120 mm	0 days	15 days
1971	20.0 °C	24.2 °C	16.2 °C	78 mm	4 days	14 days
1970	18.7 °C	23.2 °C	14.6 °C	208 mm	2 days	16 days
1969	18.4 °C	22.6 °C	14.5 °C	72 mm	0 days	13 days
1968	18.8 °C	23.4 °C	14.5 °C	71 mm	1 day	9 days
1967	17.4 °C	22.1 °C	12.8 °C	65 mm	0 days	8 days
1966	17.5 °C	22.1 °C	12.9 °C	28 mm	2 days	7 days
1965	18.1 °C	22.1 °C	14.6 °C	191 mm	0 days	10 days
1964	18.2 °C	22.9 °C	14.1 °C	62 mm	5 days	9 days
1963	18.1 °C	23.1 °C	13.8 °C	47 mm	0 days	8 days
1962	16.9 °C	21.5 °C	12.4 °C	47 mm	0 days	9 days
1961	19.8 °C	24.7 °C	15.4 °C	202 mm	6 days	14 days
1960	20.4 °C	24.7 °C	16.8 °C	57 mm	7 days	14 days
1959	19.9 °C	24.3 °C	16.0 °C	86 mm	5 days	10 days
1958	18.4 °C	22.6 °C	14.6 °C	55 mm	0 days	8 days
1957	17.2 °C	21.7 °C	13.2 °C	34 mm	1 day	4 days
1956	17.6 °C	22.7 °C	12.9 °C	13 mm	0 days	3 days
1955	19.2 °C	24.0 °C	14.7 °C	46 mm	4 days	5 days
1954	19.9 °C	24.6 °C	15.6 °C	42 mm	3 days	6 days
1953	18.7 °C	24.3 °C	13.8 °C	40 mm	6 days	5 days
1952	18.1 °C	23.4 °C	13.0 °C	39 mm	4 days	5 days
1951	16.7 °C	21.2 °C	12.7 °C	92 mm	0 days	11 days
1950	17.9 °C	21.5 °C	14.7 °C	65 mm	0 days	8 days
1949	15.7 °C	20.3 °C	11.6 °C	72 mm	0 days	9 days
1948	19.9 °C	24.2 °C	15.8 °C	83 mm	3 days	8 days
1947	19.0 °C	23.4 °C	15.1 °C	91 mm	4 days	8 days
1946	18.7 °C	23.0 °C	14.5 °C	24 mm	1 day	4 days
1945	18.8 °C	22.2 °C	15.2 °C	187 mm	3 days	15 days
1944	19.1 °C	23.0 °C	15.6 °C	38 mm	0 days	9 days
1943	16.1 °C	20.2 °C	12.3 °C	41 mm	0 days	5 days
1942	17.4 °C	21.1 °C	14.0 °C	91 mm	0 days	8 days
1941	20.1 °C	24.4 °C	16.2 °C	90 mm	2 days	10 days
1940	17.0 °C	21.0 °C	13.2 °C	12 mm	0 days	4 days

September records

Hottest day

36.3 °C

September 1, 1953 estimate

Nearby station: 38.3 °C on September 1, 1953 measured

Coldest night

1.4 °C

September 23, 1974 estimate

Nearby station: -1.7 °C on September 28, 1942 measured

Wettest day

72 mm

September 29, 1973 estimate

The weather on your birthday in Chicago

Any day since 1940: high, low, rain, snow, and how warm it was compared with the same date in every other year.

Questions & answers

How warm is Chicago in September?

Highs average 23.1 °C and lows 14.7 °C. A typical September brings 2 hot days (30 °C or more) and 0 frost days.

Does it rain a lot in Chicago in September?

About 75 mm falls in September, over some 9 days with at least 1 mm. The wettest September was 2008 (225 mm), the driest 1979 (6 mm).

What was the warmest September in Chicago?

2005, with a mean temperature of 21.3 °C. The coldest was 1949 (15.7 °C). The last one, 2025, ranks 23 of 86.