Climate almanac
DeKalb
Illinois, United States · 41.93°, -88.75°
What is the weather like in DeKalb in September?
In September, DeKalb is typically 77°F (25°C) during the day and 58°F (14°C) at night. The month brings about 3.7 in (94 mm) of precipitation in total.
- Average high77°F (25°C)
- Average low58°F (14°C)
- Precipitation3.7 in (94 mm)
- Clear or mostly clear days14
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)