Jacksonville (IL) Weather & Climate: Best Time to Visit

Depending on the time of the year, temperatures range from very warm to chilly in Jacksonville. Average daytime temperatures reach a very warm 30°C (86°F) in July. In January, the coolest month of the year, temperatures drop to a chilly 2°C (36°F).

At night, temperatures range from around 18°C (64°F) in July to -8°C (18°F) in January.

Check out our detailed temperature page for more information.

Temperature ranges by month

Jacksonville has a relatively rain/snowy climate with high precipitation levels, averaging 1091 mm (43 in) of rain/snowfall annually. Jacksonville can be quite wet during June, receiving approximately 154 mm (6.1 in) of precipitation over 13 rainy days.

In contrast, during the driest month (January), you will experience much drier conditions, with 50 mm (2 in) of precipitation spread across 8 snowy/rainy days. For more details, please visit our Jacksonville Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Jacksonville can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 10.7 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 4.3 hours of sunlight per day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in Jacksonville.

The city experiences its highest humidity in December, reaching 78%. In April, the humidity drops to its lowest level at 65%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year