- Country: US
- State: IL
- Latitude: 41.856
- Longitude: -87.609
High Temperatures
On May 15 in NORTHERLY ISLAND the average high temperature is 69.8 °F (21.0 °C). The lowest recored high temperature was 48.7 °F (9.3 °C) in 2014 and the highest recored high temperature was 90.0 °F (32.2 °C) in 2025. The high temperature is usually* between 62.0 °F (16.7 °C) and 77.7 °F (25.4 °C). About a quarter of the time, the high temperature is less than 62.0 °F (16.7 °C), and another quarter of the time, the high temperature is greater than and 77.7 °F (25.4 °C). About 95% of the time, the high temperature has been between 47.0 °F (8.3 °C) and 92.7 °F (33.7 °C).
Low Temperatures
On May 15 in NORTHERLY ISLAND the average low temperature is 49.7 °F (9.8 °C). The lowest recored low temperature was 41.4 °F (5.2 °C) in 2014 and the lowest recored low temperature was 60.1 °F (15.6 °C) in 2013. The low temperature is usually* between 45.4 °F (7.4 °C) and 54.0 °F (12.2 °C). About a quarter of the time, the low temperature is less than 45.4 °F (7.4 °C), and another quarter of the time, the low temperature is greater than and 54.0 °F (12.2 °C). About 95% of the time, the low temperature has been between 37.2 °F (2.9 °C) and 62.3 °F (16.8 °C).
Frost
On May 15 in NORTHERLY ISLAND expect the temperatures to drop below freezing for a risk of frost about 0.3% 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