- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On September 18 in NORTHERLY ISLAND the average high temperature is 76.7 °F (24.8 °C). The lowest recored high temperature was 64.9 °F (18.3 °C) in 2014 and the highest recored high temperature was 88.0 °F (31.1 °C) in 2021. The high temperature is usually* between 71.6 °F (22.0 °C) and 81.8 °F (27.7 °C). About a quarter of the time, the high temperature is less than 71.6 °F (22.0 °C), and another quarter of the time, the high temperature is greater than and 81.8 °F (27.7 °C). About 95% of the time, the high temperature has been between 62.0 °F (16.6 °C) and 91.5 °F (33.1 °C).
Low Temperatures
On September 18 in NORTHERLY ISLAND the average low temperature is 61.3 °F (16.3 °C). The lowest recored low temperature was 51.8 °F (11.0 °C) in 2012 and the lowest recored low temperature was 69.1 °F (20.6 °C) in 2022. The low temperature is usually* between 57.8 °F (14.3 °C) and 64.9 °F (18.3 °C). About a quarter of the time, the low temperature is less than 57.8 °F (14.3 °C), and another quarter of the time, the low temperature is greater than and 64.9 °F (18.3 °C). About 95% of the time, the low temperature has been between 51.1 °F (10.6 °C) and 71.6 °F (22.0 °C).
Frost
On September 18 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