Climate almanac
Chester
Illinois, United States · 37.91°, -89.82°
What is the climate like in Chester?
The best time to visit Chester is typically August – October, with trip comfort peaking in September (7.2/10). Chester is warmest in July, when daily highs average 89°F (32°C), and coolest in January, when lows fall to about 28°F (-2°C). The wettest month is typically April and the driest is November; the year sees roughly 48 in (1218 mm) of precipitation.
- Best time to visitAugust – October — comfort peaks in September (7.2/10)
- Warmest monthJuly — average high 89°F (32°C)
- Coolest monthJanuary — average low 28°F (-2°C)
- Wettest monthApril (5.7 in (144 mm))
- Driest monthNovember (2.8 in (71 mm))
- Annual precipitation48 in (1218 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
- Records fromPerryville Wtp, 22 km away (1907-2026)