Station information
- Integrated Surface Dataset (ISD) station ID: 997338
- Country: US
- State: IL
- Latitude: 42.0
- Longitude: -87.5
High Temperatures
On September 20 in CHICAGO the average high temperature is 74.4 °F (23.6 °C). The lowest recored high temperature was 64.9 °F (18.3 °C) in 2015 and the highest recored high temperature was 86.5 °F (30.3 °C) in 2017. The high temperature is usually* between 69.5 °F (20.8 °C) and 79.4 °F (26.3 °C). About a quarter of the time, the high temperature is less than 69.5 °F (20.8 °C), and another quarter of the time, the high temperature is greater than and 79.4 °F (26.3 °C). About 95% of the time, the high temperature has been between 60.0 °F (15.5 °C) and 88.9 °F (31.6 °C).
Low Temperatures
On September 20 in CHICAGO the average low temperature is 65.1 °F (18.4 °C). The lowest recored low temperature was 56.7 °F (13.7 °C) in 2011 and the lowest recored low temperature was 73.9 °F (23.3 °C) in 2024. The low temperature is usually* between 61.5 °F (16.4 °C) and 68.8 °F (20.4 °C). About a quarter of the time, the low temperature is less than 61.5 °F (16.4 °C), and another quarter of the time, the low temperature is greater than and 68.8 °F (20.4 °C). About 95% of the time, the low temperature has been between 54.5 °F (12.5 °C) and 75.8 °F (24.3 °C).
Frost
On September 20 in CHICAGO expect the temperatures to drop below freezing for a risk of frost about 0.0% of the time.
Data Source(s)
The data used to compute the average high/low temperatures for this location were taken from the following stations:
- CHICAGO — Integrated Surface Dataset (ISD) station ID: 997338 — from year 2005 to 2024