June in Fontana averages a daily high of 30.2°C with nights around 15.5°C. Rain is rare — about 0.3 wet days and 0.3mm across the month. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Fontana is March–May.
Based on ONTARIO INTERNATIONAL AIRPORT, CA US (13.8km), 1995–2024. 27 years of June data.