Last updated: June 24, 2025
In September, the average temperature in Hillsboro, United States hovers around 16°C (60°F). During this time, temperatures can fluctuate, with a minimum of -2°C (28°F) and a maximum reaching up to 32°C (90°F). Expect about 72 mm (2.8 in) of precipitation spread over 8 days, coupled with an average humidity of 77%, creating a unique blend of weather conditions to experience.
In September in Hillsboro, the average temperature is 16°C (60°F). The maximum can reach 32°C (90°F), while the minimum can be as low as -2°C (28°F). This diverse range of temperatures makes Hillsboro an ideal destination for travelers seeking both warm days and cooler nights.
In Hillsboro in September, the precipitation amount is 72 mm (2.8 in) over the course of 8 days.
In Hillsboro in September, humidity is 77%. With an average temperature of 16°C (60°F), this humidity feels like a moist blanket wrapping around you, making outdoor activities a bit uncomfortable and requiring frequent hydration as you soak in the vibrant local culture.
In Hillsboro in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Hillsboro.
UV Risk Categories
Weather in Hillsboro varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hillsboro, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -12°C (10°F) | 18 mm (0.7 inches) | 90% | low |
| February Weather | -13°C (9°F) | 20 mm (0.8 inches) | 92% | moderate |
| March Weather | -3°C (27°F) | 26 mm (1.0 inches) | 85% | moderate |
| April Weather | 4°C (40°F) | 43 mm (1.7 inches) | 81% | high |
| May Weather | 13°C (57°F) | 54 mm (2.1 inches) | 75% | very high |
| June Weather | 21°C (69°F) | 90 mm (3.5 inches) | 79% | very high |
| July Weather | 22°C (73°F) | 60 mm (2.4 inches) | 76% | very high |
| August Weather | 20°C (69°F) | 85 mm (3.4 inches) | 78% | very high |
| September Weather | 16°C (60°F) | 72 mm (2.8 inches) | 77% | high |
| October Weather | 7°C (44°F) | 80 mm (3.2 inches) | 79% | moderate |
| November Weather | -2°C (28°F) | 23 mm (0.9 inches) | 86% | moderate |
| December Weather | -8°C (18°F) | 39 mm (1.6 inches) | 86% | low |