Climate almanac
Alton
Illinois, United States · 38.89°, -90.18°
What is the weather like in Alton in May?
In May, Alton is typically 77°F (25°C) during the day and 59°F (15°C) at night. The month brings about 5.1 in (130 mm) of precipitation in total.
- Average high77°F (25°C)
- Average low59°F (15°C)
- Precipitation5.1 in (130 mm)
- Clear or mostly clear days9
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)