October 21 - Chicago - Weather History and Averages

High Temperatures

On October 21 in Chicago, IL (Illinois), USA the average high temperature is 63.2 °F (17.3 °C). The lowest recored high temperature was 39.9 °F (4.4 °C) in 1987 and the highest recored high temperature was 87.1 °F (30.6 °C) in 1953. The high temperature is usually* between 56.7 °F (13.7 °C) and 69.7 °F (20.9 °C). About a quarter of the time, the high temperature is less than 56.7 °F (13.7 °C), and another quarter of the time, the high temperature is greater than and 69.7 °F (20.9 °C). About 95% of the time, the high temperature has been between 44.3 °F (6.8 °C) and 82.0 °F (27.8 °C).

Low Temperatures

On October 21 in Chicago, IL (Illinois), USA the average low temperature is 44.7 °F (7.0 °C). The lowest recored low temperature was 21.9 °F (-5.6 °C) in 1952 and the lowest recored low temperature was 71.1 °F (21.7 °C) in 1979. The low temperature is usually* between 39.2 °F (4.0 °C) and 50.1 °F (10.1 °C). About a quarter of the time, the low temperature is less than 39.2 °F (4.0 °C), and another quarter of the time, the low temperature is greater than and 50.1 °F (10.1 °C). About 95% of the time, the low temperature has been between 28.8 °F (-1.8 °C) and 60.5 °F (15.9 °C).

Frost

On October 21 in Chicago, IL (Illinois), USA expect the temperatures to drop below freezing for a risk of frost about 5.9% 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: