Climate almanac
Eureka
Illinois, United States · 40.72°, -89.27°
What is the weather like in Eureka in September?
In September, Eureka is typically 80°F (27°C) during the day and 59°F (15°C) at night. The month brings about 2.5 in (65 mm) of precipitation in total.
- Average high80°F (27°C)
- Average low59°F (15°C)
- Precipitation2.5 in (65 mm)
- Clear or mostly clear days14
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)