January in Hillsboro averages a daily high of 8.2°C with nights around 1°C. Expect roughly 19.5 wet days totalling 135.7mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Hillsboro is June–September.
Based on PORTLAND HILLSBORO AIRPORT, OR US (3.8km), 1995–2024. 25 years of January data.