- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On September 20 in NORTHERLY ISLAND the average high temperature is 76.7 °F (24.8 °C). The lowest recored high temperature was 67.6 °F (19.8 °C) in 2020 and the highest recored high temperature was 87.1 °F (30.6 °C) in 2016. The high temperature is usually* between 72.2 °F (22.3 °C) and 81.1 °F (27.3 °C). About a quarter of the time, the high temperature is less than 72.2 °F (22.3 °C), and another quarter of the time, the high temperature is greater than and 81.1 °F (27.3 °C). About 95% of the time, the high temperature has been between 63.8 °F (17.6 °C) and 89.6 °F (32.0 °C).
Low Temperatures
On September 20 in NORTHERLY ISLAND the average low temperature is 61.2 °F (16.2 °C). The lowest recored low temperature was 48.0 °F (8.9 °C) in 2020 and the lowest recored low temperature was 68.7 °F (20.4 °C) in 2013. The low temperature is usually* between 57.3 °F (14.1 °C) and 65.1 °F (18.4 °C). About a quarter of the time, the low temperature is less than 57.3 °F (14.1 °C), and another quarter of the time, the low temperature is greater than and 65.1 °F (18.4 °C). About 95% of the time, the low temperature has been between 49.9 °F (9.9 °C) and 72.5 °F (22.5 °C).
Frost
On September 20 in NORTHERLY ISLAND 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:
- NORTHERLY ISLAND — Integrated Surface Dataset (ISD) station ID: 998499 — from year 2012 to 2024