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December Weather in Hillsboro, United States

Last updated: June 24, 2025

In December, the average temperature in Hillsboro, United States hovers around 9°C (48°F), with lows dipping to -6°C (22°F) and highs reaching 23°C (73°F). Expect around 144 mm (5.7 in) of precipitation spread over 11 days, contributing to a notable average humidity of 88%.

December Temperature in Hillsboro

In December in Hillsboro, the average temperature is 9°C (48°F). Maximums can reach 23°C (73°F), and minimums can drop as low as -6°C (22°F). Be prepared for a wide range of temperatures when traveling during this time.

December Weather in Hillsboro: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Hillsboro, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hillsboro, December typically has an average temperature of 9°C (48°F), with highs reaching up to 23°C (73°F) and lows dropping to around -6°C (22°F).
JanFebMarAprMayJunJulAugSepOctNovDec444956627278818076665148
Data source: Temperature data for Hillsboro generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

December Precipitation in Hillsboro

In Hillsboro in December, the precipitation amount is 144 mm (5.7 in) during 11 days, indicating a relatively wet period for the region.

December Precipitation Trends in Hillsboro

The chart displays monthly precipitation patterns in Hillsboro, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Hillsboro, December typically receives around 144 mm (5.7 inches) of precipitation spread over approximately 11 days.
JanFebMarAprMayJunJulAugSepOctNovDec1141781751471051189910710210871144
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Hillsboro

In Hillsboro in December, humidity is 88%. With an average temperature of 9°C (48°F), this humidity feels like a damp chill settling into your bones, making outdoor exploration feel heavy and oppressive.

December Average Humidity in Hillsboro

This chart illustrates the average monthly humidity levels in Hillsboro, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Hillsboro is approximately 88%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%85%82%83%82%78%67%64%75%87%89%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Hillsboro

In Hillsboro in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Hillsboro for better planning.

Maximum UV Index Levels in Hillsboro for December

The chart shows the monthly maximum UV Index (UVI) for Hillsboro in December, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In December, the maximum UV index in Hillsboro typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46810111111109754
Data source: Hillsboro December UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How December Weather in Hillsboro Compares to Other Months

Weather in Hillsboro varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Hillsboro, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Hillsboro, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather7°C (44°F)114 mm (4.5 inches)87%moderate
February Weather9°C (49°F)178 mm (7.0 inches)87%high
March Weather13°C (56°F)175 mm (6.9 inches)85%very high
April Weather17°C (62°F)147 mm (5.8 inches)82%very high
May Weather22°C (72°F)105 mm (4.1 inches)83%extreme
June Weather25°C (78°F)118 mm (4.7 inches)82%extreme
July Weather27°C (81°F)99 mm (3.9 inches)78%extreme
August Weather27°C (80°F)107 mm (4.2 inches)67%very high
September Weather24°C (76°F)102 mm (4.0 inches)64%very high
October Weather19°C (66°F)108 mm (4.2 inches)74%high
November Weather11°C (51°F)71 mm (2.8 inches)87%moderate
December Weather9°C (48°F)144 mm (5.7 inches)88%moderate

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