Climate almanac
Ottawa
Illinois, United States · 41.35°, -88.84°
What is the weather like in Ottawa in August?
In August, Ottawa is typically 83°F (28°C) during the day and 65°F (18°C) at night. The month brings about 3.4 in (87 mm) of precipitation in total.
- Average high83°F (28°C)
- Average low65°F (18°C)
- Precipitation3.4 in (87 mm)
- Clear or mostly clear days13
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)