Chicago IL Average Temperatures by Month

The numbers here tell you how hot and cold the weather usually is in Chicago, Illinois during each month of the year.

The average high and low temperatures are listed below by month and annually for Chicago, in both degrees Fahrenheit and Celsius.

Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.

To find out how often it rises over 70, 80 or 90 °F each month in Chicago, scroll down farther. There are also monthly and yearly counts of days with freezing weather.

The first set of high and low temperatures are averages for 2010 to 2019. Everything else here is based on 1991 to 2020 weather.

10-year temperature averages for Chicago, 2010 to 2019
High °F	Low °F		High °C	Low °C
31	17	January	-1	-9
35	19	February	1	-7
47	30	March	8	-1
59	39	April	15	4
71	51	May	22	10
80	61	June	27	16
85	66	July	29	19
83	65	August	28	18
76	58	September	24	14
63	45	October	17	7
48	32	November	9	0
37	24	December	3	-4
59	42	Year	15	6

30-year temperature averages for Chicago, 1991 to 2020
High °F	Low °F		High °C	Low °C
33	20	January	0	-7
37	23	February	3	-5
48	32	March	9	0
60	42	April	16	5
72	52	May	22	11
81	63	June	27	17
85	68	July	30	20
83	67	August	28	19
77	59	September	25	15
64	47	October	18	8
50	35	November	10	2
38	25	December	3	-4
61	44	Year	16	7

Days of Hot Weather in Chicago

Temperatures typically reach 100 °F in Chicago just once a year. But it does get into the 90s on an average 21 days a year.

The days are above 50 degrees from May to September and nearly every day October. But Chicago only gets that warm for a few days in winter.

Days per month in Chicago of at least 70, 80 or 90 °F
	70 °F 21 °C	80 °F 27 °C	90 °F 32 °C
January	0	0	0
February	0	0	0
March	2	0	0
April	6	2	0
May	17	8	1
June	27	18	5
July	31	24	8
August	30	22	5
September	23	11	2
October	9	2	0
November	1	0	0
December	0	0	0
Year	145	86	21

Freezing Temperatures in Chicago

Freezing temperatures can occur anytime from October to April in Chicago. Typically, for four days each year the thermometer drops to zero degrees Fahrenheit (-18 °C) or colder.

The daytime temperature doesn't rise above freezing for 39 days annually, on average. November to March is when weather this cold can last all day.

Days in Chicago with temperature that drops to 10, 20, or 32 °F or lower
	10 °F -12 °C	20 °F -8 °C	32 °F 0 °C
January	7	16	27
February	4	11	23
March	1	4	18
April	0	0	4
May	0	0	0
June	0	0	0
July	0	0	0
August	0	0	0
September	0	0	0
October	0	0	1
November	0	2	12
December	4	10	24
Year	16	42	108

Chicago Temperatures: Averages by Month

Days of Hot Weather in Chicago

Freezing Temperatures in Chicago

References

More on Weather in Illinois