Hillsboro (OR) Weather & Climate: Best Time to Visit

Visitors to Hillsboro can expect significant temperature changes throughout the year. Average daytime temperatures reach a comfortable 28°C (82°F) in August. In December, the coolest month of the year, temperatures drop to a chilly 7°C (45°F).

At night, temperatures range from around 13°C (55°F) in August to 1°C (34°F) in December.

Check out our detailed temperature page for more information.

Temperature ranges by month

Generally, Hillsboro experiences moderate precipitation patterns, averaging 963 mm (38 in) yearly. Hillsboro can be quite wet during December, receiving approximately 185 mm (7.3 in) of precipitation over 22 rainy days.

In contrast, during the driest month (July), you will experience much drier conditions, with 8.8 mm (0.3 in) of precipitation spread across 4 rainy days days. For more details, please visit our Hillsboro Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Hillsboro can be enjoyed more throughout the sunniest month of July under a blue sky, with approximately 11.1 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 2.1 hours of sunlight per day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

The relative humidity is high throughout the year in Hillsboro.

The city experiences its highest humidity in December, reaching 83%. In July, the humidity drops to its lowest level at 63%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year