August in Hillsboro averages a daily high of 28.2°C with nights around 11.4°C. Expect roughly 3.2 wet days totalling 11.4mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Hillsboro is June–September.
Based on PORTLAND HILLSBORO AIRPORT, OR US (3.8km), 1995–2024. 27 years of August data.