Station information
- Integrated Surface Dataset (ISD) station ID: 998499
- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On April 21 in NORTHERLY ISLAND the average high temperature is 60.0 °F (15.6 °C). The lowest recored high temperature was 42.1 °F (5.6 °C) in 2021 and the highest recored high temperature was 75.6 °F (24.2 °C) in 2023. The high temperature is usually* between 53.3 °F (11.8 °C) and 66.8 °F (19.3 °C). About a quarter of the time, the high temperature is less than 53.3 °F (11.8 °C), and another quarter of the time, the high temperature is greater than and 66.8 °F (19.3 °C). About 95% of the time, the high temperature has been between 40.5 °F (4.7 °C) and 79.6 °F (26.4 °C).
Low Temperatures
On April 21 in NORTHERLY ISLAND the average low temperature is 40.8 °F (4.9 °C). The lowest recored low temperature was 34.0 °F (1.1 °C) in 2021 and the lowest recored low temperature was 52.5 °F (11.4 °C) in 2014. The low temperature is usually* between 37.9 °F (3.3 °C) and 43.8 °F (6.5 °C). About a quarter of the time, the low temperature is less than 37.9 °F (3.3 °C), and another quarter of the time, the low temperature is greater than and 43.8 °F (6.5 °C). About 95% of the time, the low temperature has been between 32.2 °F (0.1 °C) and 49.4 °F (9.7 °C).
Frost
On April 21 in NORTHERLY ISLAND expect the temperatures to drop below freezing for a risk of frost about 2.2% 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