About Mount Olive, IL's Climate & Weather History

With a population of around 2,000, Mount Olive sits in Illinois, United States. The city operates in the Central Time Zone.

In 2025, Mount Olive recorded an average annual temperature of 56°F. The hottest temperatures reached 96°F in September; the coolest were -4°F in January. Total precipitation for the year was 41 inches, with the wettest month being April. Snowfall for the year totaled approximately 8 inches.