Climate almanac
Ontario
California, United States · 34.06°, -117.65°
What is the weather like in Ontario in December?
In December, Ontario is typically 66°F (19°C) during the day and 46°F (8°C) at night. The month brings about 2.9 in (73 mm) of precipitation in total.
- Average high66°F (19°C)
- Average low46°F (8°C)
- Precipitation2.9 in (73 mm)
- Clear or mostly clear days14
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)