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December Weather in San Fernando, Mexico

Last updated: August 27, 2025

In December, the average temperature in San Fernando, Mexico hovers around 18°C (66°F). Expect a range of temperatures that can dip to a chilly 2°C (35°F) and soar up to a warm 33°C (92°F). With 13 mm (0.5 in) of precipitation spread over 2 days, you might want to carry an umbrella. The air is notably humid, with an average humidity level of 86%, adding to the atmosphere of this vibrant locale.

December Temperature in San Fernando

In December in San Fernando, the average temperature is 18°C (66°F). Maximums can reach 33°C (92°F) and minimums can be as low as 2°C (35°F). Be prepared for a wide range of temperatures, making it essential to pack both light clothing and warmer layers for your travels.

December Weather in San Fernando: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in San Fernando, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Fernando, December typically has an average temperature of 18°C (66°F), with highs reaching up to 33°C (92°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec636672778285858782776965
Data source: Temperature data for San Fernando 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 San Fernando

In San Fernando in December, the precipitation amount is 13 mm (0.5 in) over a span of 2 days.

December Precipitation Trends in San Fernando

The chart displays monthly precipitation patterns in San Fernando, 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 San Fernando, December typically receives around 13 mm (0.5 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec2416363058738625109873313
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Fernando

In San Fernando in December, humidity is 86%. With an average temperature of 18°C (66°F), this humidity feels like walking through a warm, thick blanket—making traveling feel heavy and the air almost tangible, which can quickly lead to fatigue and a sense of weariness as you explore.

December Average Humidity in San Fernando

This chart illustrates the average monthly humidity levels in San Fernando, 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 San Fernando is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%83%78%81%82%74%68%67%75%78%83%86%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Fernando

In San Fernando in December, the maximum UV index is 6, which corresponds to a high Exposure Category. The time to burn is approximately 25 minutes. To find the hourly UV index in San Fernando, you can refer to this Hourly UV Index in San Fernando.

Maximum UV Index Levels in San Fernando for December

The chart shows the monthly maximum UV Index (UVI) for San Fernando 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 San Fernando typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec79111212121212111086
Data source: San Fernando 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 San Fernando Compares to Other Months

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

This table compares monthly weather conditions in San Fernando, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather17°C (63°F)24 mm (0.9 inches)84%high
February Weather19°C (67°F)16 mm (0.6 inches)83%very high
March Weather22°C (73°F)36 mm (1.4 inches)78%extreme
April Weather25°C (78°F)30 mm (1.2 inches)81%extreme
May Weather28°C (83°F)58 mm (2.3 inches)82%extreme
June Weather29°C (85°F)72 mm (2.9 inches)74%extreme
July Weather30°C (86°F)86 mm (3.4 inches)68%extreme
August Weather30°C (87°F)25 mm (1.0 inches)67%extreme
September Weather28°C (83°F)109 mm (4.3 inches)75%extreme
October Weather25°C (77°F)87 mm (3.4 inches)78%very high
November Weather21°C (70°F)33 mm (1.3 inches)83%very high
December Weather18°C (66°F)13 mm (0.5 inches)86%high

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