- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On April 20 in NORTHERLY ISLAND the average high temperature is 59.6 °F (15.3 °C). The lowest recored high temperature was 41.5 °F (5.3 °C) in 2013 and the highest recored high temperature was 77.5 °F (25.3 °C) in 2023. The high temperature is usually* between 52.5 °F (11.4 °C) and 66.6 °F (19.2 °C). About a quarter of the time, the high temperature is less than 52.5 °F (11.4 °C), and another quarter of the time, the high temperature is greater than and 66.6 °F (19.2 °C). About 95% of the time, the high temperature has been between 39.0 °F (3.9 °C) and 80.1 °F (26.7 °C).
Low Temperatures
On April 20 in NORTHERLY ISLAND the average low temperature is 40.2 °F (4.6 °C). The lowest recored low temperature was 32.7 °F (0.4 °C) in 2013 and the lowest recored low temperature was 46.0 °F (7.8 °C) in 2015. The low temperature is usually* between 37.1 °F (2.8 °C) and 43.3 °F (6.3 °C). About a quarter of the time, the low temperature is less than 37.1 °F (2.8 °C), and another quarter of the time, the low temperature is greater than and 43.3 °F (6.3 °C). About 95% of the time, the low temperature has been between 31.2 °F (-0.4 °C) and 49.2 °F (9.5 °C).
Frost
On April 20 in NORTHERLY ISLAND expect the temperatures to drop below freezing for a risk of frost about 3.7% 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