September 17 - Chicago - Weather History and Averages

High Temperatures

On September 17 in Chicago, IL (Illinois), USA the average high temperature is 75.3 °F (24.0 °C). The lowest recored high temperature was 54.0 °F (12.2 °C) in 1981 and the highest recored high temperature was 93.0 °F (33.9 °C) in 1955. The high temperature is usually* between 70.1 °F (21.1 °C) and 80.5 °F (26.9 °C). About a quarter of the time, the high temperature is less than 70.1 °F (21.1 °C), and another quarter of the time, the high temperature is greater than and 80.5 °F (26.9 °C). About 95% of the time, the high temperature has been between 60.2 °F (15.6 °C) and 90.4 °F (32.4 °C).

Low Temperatures

On September 17 in Chicago, IL (Illinois), USA the average low temperature is 57.4 °F (14.1 °C). The lowest recored low temperature was 37.0 °F (2.8 °C) in 1984 and the lowest recored low temperature was 71.6 °F (22.0 °C) in 2024. The low temperature is usually* between 52.9 °F (11.6 °C) and 62.0 °F (16.6 °C). About a quarter of the time, the low temperature is less than 52.9 °F (11.6 °C), and another quarter of the time, the low temperature is greater than and 62.0 °F (16.6 °C). About 95% of the time, the low temperature has been between 44.3 °F (6.8 °C) and 70.6 °F (21.4 °C).

Frost

On September 17 in Chicago, IL (Illinois), USA expect the temperatures to drop below freezing for a risk of frost about 0.0% of the time.

Usually* in this context means around 50% of the time, assuming a normal distribution of values.

Data Source(s)

The data used to compute the average high/low temperatures for this location were taken from the following stations: