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December Weather in Oeiras, Portugal

Last updated: August 27, 2025

In December, the average temperature in Oeiras, Portugal is a cool 13°C (56°F), with a minimum of 6°C (43°F) and a maximum reaching up to 18°C (65°F). Expect 62 mm (2.4 in) of precipitation over 8 days, contributing to an average humidity of 85%. Prepare for a refreshing month!

December Temperature in Oeiras

In December in Oeiras, the average temperature is 13°C (56°F), with maximums reaching up to 18°C (65°F) and minimums dipping as low as 6°C (43°F). This mild climate makes Oeiras a great destination for travelers looking to explore comfortably.

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

The chart illustrates December temperature patterns in Oeiras, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Oeiras, December typically has an average temperature of 13°C (56°F), with highs reaching up to 18°C (65°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec535556586365686968655956
Data source: Temperature data for Oeiras 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 Oeiras

In Oeiras in December, the precipitation amount is 62 mm (2.4 in) over the course of 8 days.

December Precipitation Trends in Oeiras

The chart displays monthly precipitation patterns in Oeiras, 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 Oeiras, December typically receives around 62 mm (2.4 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec3753667336115327468062
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Oeiras

In Oeiras in December humidity is 85%. With an average temperature of 13°C (56°F), this humidity feels like a damp chill that wraps around you, making outdoor activities feel heavier and less enjoyable, as layers of clothing cling to the skin and breath becomes visible in the moist air.

December Average Humidity in Oeiras

This chart illustrates the average monthly humidity levels in Oeiras, 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 Oeiras is approximately 85%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%75%72%70%70%63%60%60%68%74%83%85%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Oeiras

In Oeiras in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Oeiras, you can check the information here.

Maximum UV Index Levels in Oeiras for December

The chart shows the monthly maximum UV Index (UVI) for Oeiras 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 Oeiras typically reaches 3, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910111098643
Data source: Oeiras 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 Oeiras Compares to Other Months

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

This table compares monthly weather conditions in Oeiras, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather12°C (53°F)37 mm (1.5 inches)85%moderate
February Weather13°C (55°F)53 mm (2.1 inches)75%moderate
March Weather14°C (57°F)66 mm (2.6 inches)72%high
April Weather15°C (59°F)73 mm (2.9 inches)70%very high
May Weather17°C (63°F)36 mm (1.4 inches)70%very high
June Weather18°C (66°F)11 mm (0.4 inches)63%extreme
July Weather20°C (68°F)5 mm (0.2 inches)60%very high
August Weather20°C (69°F)3 mm (0.1 inches)60%very high
September Weather20°C (68°F)27 mm (1.1 inches)67%very high
October Weather18°C (65°F)46 mm (1.8 inches)74%high
November Weather15°C (59°F)80 mm (3.2 inches)83%moderate
December Weather13°C (56°F)62 mm (2.4 inches)85%moderate

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