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December Weather in Rio Maior, Portugal

Last updated: August 27, 2025

In December, the average temperature in Rio Maior, Portugal is a pleasant 12°C (54°F). Expect a cool minimum of 1°C (35°F) and a comfortable maximum of 19°C (66°F). With 64 mm (2.5 in) of precipitation spread over 9 days, don't forget to pack an umbrella! The average humidity sits at a high 85%, making it a good time to enjoy cozy indoor activities.

December Temperature in Rio Maior

In December in Rio Maior, the average temperature is 12°C (54°F), with a maximum reaching 19°C (66°F) and a minimum as low as 1°C (35°F). This makes Rio Maior an ideal destination for travelers seeking a mild climate during this time of year.

December Weather in Rio Maior: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Rio Maior, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Rio Maior, December typically has an average temperature of 12°C (54°F), with highs reaching up to 19°C (66°F) and lows dropping to around 1°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec515456596466707069645754
Data source: Temperature data for Rio Maior 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 Rio Maior

In Rio Maior in December, the precipitation amount is 64 mm (2.5 in) over a span of 9 days.

December Precipitation Trends in Rio Maior

The chart displays monthly precipitation patterns in Rio Maior, 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 Rio Maior, December typically receives around 64 mm (2.5 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec4153748339166627588864
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Rio Maior

In Rio Maior in December, humidity is 85%. With an average temperature of 12°C (54°F), this humidity feels like a heavy blanket wrapping around you, making traveling not only uncomfortable but also exhausting as the damp air clings to your skin and slows your movements.

December Average Humidity in Rio Maior

This chart illustrates the average monthly humidity levels in Rio Maior, 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 Rio Maior 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 Rio Maior

In Rio Maior 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 Rio Maior, you can check the information here.

Maximum UV Index Levels in Rio Maior for December

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

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

This table compares monthly weather conditions in Rio Maior, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (51°F)41 mm (1.6 inches)85%moderate
February Weather12°C (54°F)53 mm (2.1 inches)75%moderate
March Weather13°C (56°F)74 mm (2.9 inches)72%high
April Weather15°C (59°F)82 mm (3.2 inches)70%very high
May Weather18°C (64°F)39 mm (1.5 inches)70%very high
June Weather19°C (67°F)16 mm (0.6 inches)63%extreme
July Weather21°C (70°F)6 mm (0.2 inches)60%very high
August Weather21°C (70°F)6 mm (0.2 inches)60%very high
September Weather21°C (69°F)27 mm (1.1 inches)67%very high
October Weather18°C (65°F)58 mm (2.3 inches)74%high
November Weather14°C (57°F)88 mm (3.5 inches)83%moderate
December Weather12°C (54°F)64 mm (2.5 inches)85%moderate

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