Climate almanac
St. Charles
Illinois, United States · 41.91°, -88.31°
What is the climate like in St. Charles?
The best time to visit St. Charles is typically August – September, with trip comfort peaking in September (7.0/10). St. Charles is warmest in July, when daily highs average 84°F (29°C), and coolest in January, when lows fall to about 19°F (-7°C). The wettest month is typically May and the driest is February; the year sees roughly 42 in (1063 mm) of precipitation.
- Best time to visitAugust – September — comfort peaks in September (7.0/10)
- Warmest monthJuly — average high 84°F (29°C)
- Coolest monthJanuary — average low 19°F (-7°C)
- Wettest monthMay (5.2 in (132 mm))
- Driest monthFebruary (2.0 in (51 mm))
- Annual precipitation42 in (1063 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
- Records fromAurora Water, 15 km away (1893-2026)