Climate almanac
Alton
Illinois, United States · 38.89°, -90.18°
What is the weather like in Alton in August?
In August, Alton is typically 85°F (29°C) during the day and 68°F (20°C) at night. The month brings about 4.2 in (107 mm) of precipitation in total.
- Average high85°F (29°C)
- Average low68°F (20°C)
- Precipitation4.2 in (107 mm)
- Clear or mostly clear days12
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)