- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On February 18 in NORTHERLY ISLAND the average high temperature is 37.8 °F (3.2 °C). The lowest recored high temperature was 13.6 °F (-10.2 °C) in 2025 and the highest recored high temperature was 66.0 °F (18.9 °C) in 2017. The high temperature is usually* between 28.3 °F (-2.1 °C) and 47.4 °F (8.5 °C). About a quarter of the time, the high temperature is less than 28.3 °F (-2.1 °C), and another quarter of the time, the high temperature is greater than and 47.4 °F (8.5 °C). About 95% of the time, the high temperature has been between 10.1 °F (-12.2 °C) and 65.6 °F (18.7 °C).
Low Temperatures
On February 18 in NORTHERLY ISLAND the average low temperature is 18.5 °F (-7.5 °C). The lowest recored low temperature was -1.3 °F (-18.5 °C) in 2025 and the lowest recored low temperature was 30.9 °F (-0.6 °C) in 2017. The low temperature is usually* between 11.8 °F (-11.2 °C) and 25.3 °F (-3.7 °C). About a quarter of the time, the low temperature is less than 11.8 °F (-11.2 °C), and another quarter of the time, the low temperature is greater than and 25.3 °F (-3.7 °C). About 95% of the time, the low temperature has been between -1.1 °F (-18.4 °C) and 38.1 °F (3.4 °C).
Frost
On February 18 in NORTHERLY ISLAND expect the temperatures to drop below freezing for a risk of frost about 91.1% 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 2013 to 2025