Climate almanac
Winthrop Harbor
Illinois, United States · 42.48°, -87.82°
What is the climate like in Winthrop Harbor?
The best time to visit Winthrop Harbor is typically July – September, with trip comfort peaking in August (7.1/10). Winthrop Harbor is warmest in August, when daily highs average 74°F (23°C), and coolest in January, when lows fall to about 25°F (-4°C). The wettest month is typically October and the driest is February; the year sees roughly 40 in (1027 mm) of precipitation.
- Best time to visitJuly – September — comfort peaks in August (7.1/10)
- Warmest monthAugust — average high 74°F (23°C)
- Coolest monthJanuary — average low 25°F (-4°C)
- Wettest monthOctober (4.7 in (119 mm))
- Driest monthFebruary (2.5 in (64 mm))
- Annual precipitation40 in (1027 mm)
- Based on2016-2025 daily ERA5 reanalysis data (10-year normals)
- Records fromKenosha Wwtp, 9 km away (1944-2026)