Milwaukee, Wisconsin weather in September

Averages from 2021–2025 (150 days of record).

Average high: 74°F
Average low: 59°F
Rainy days: ~8 per month
Total precipitation: 3.6 in
Warmest recorded: 94°F
Coldest recorded: 38°F

Expect September days in Milwaukee, Wisconsin to top out around 74°F and cool to about 59°F overnight, with roughly 8 days of measurable rain across the month. In recent years September has ranged from 38°F to 94°F.

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Current Milwaukee, Wisconsin forecast → · Historical data by Open-Meteo (ERA5).