Climate almanac
Mount Prospect
Illinois, United States · 42.07°, -87.94°
What is the weather like in Mount Prospect in September?
In September, Mount Prospect is typically 77°F (25°C) during the day and 59°F (15°C) at night. The month brings about 3.0 in (75 mm) of precipitation in total.
- Average high77°F (25°C)
- Average low59°F (15°C)
- Precipitation3.0 in (75 mm)
- Clear or mostly clear days13
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)