June in Waterloo averages a daily high of 27.5°C with nights around 15.4°C. Expect roughly 11.8 wet days totalling 142.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Waterloo is August–September.
Based on WATERLOO MUNICIPAL AIRPORT, IA US (8.4km), 1995–2024. 30 years of June data.