July in Duluth averages a daily high of 25°C with nights around 14.7°C. Expect roughly 9.5 wet days totalling 87.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Duluth is June–September.
Based on SUPERIOR, WI US (6.8km), 1995–2024. 28 years of July data.