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December Weather in San Marcos, El Salvador

Last updated: August 23, 2025

In San Marcos, El Salvador, the average temperature in December is a pleasant 25°C (78°F). You can expect temperatures to range from a minimum of 16°C (61°F) to a maximum of 35°C (95°F). The month typically sees about 7 mm (0.3 in) of precipitation over 1 day, accompanied by an average humidity of 66%. Enjoy the mild climate!

December Temperature in San Marcos

In December in San Marcos, the average temperature is 25°C (78°F). Maximums can reach 35°C (95°F) and minimums can be as low as 16°C (61°F). This makes San Marcos an ideal destination for travelers seeking warm weather and pleasant conditions.

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

The chart illustrates December temperature patterns in San Marcos, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Marcos, December typically has an average temperature of 25°C (78°F), with highs reaching up to 35°C (95°F) and lows dropping to around 16°C (61°F).
JanFebMarAprMayJunJulAugSepOctNovDec777981818078808078787877
Data source: Temperature data for San Marcos 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 Marcos

In San Marcos in December, the precipitation amount is 7 mm (0.3 in) over the course of 1 day.

December Precipitation Trends in San Marcos

The chart displays monthly precipitation patterns in San Marcos, 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 Marcos, December typically receives around 7 mm (0.3 inches) of precipitation spread over approximately 1 days.
JanFebMarAprMayJunJulAugSepOctNovDec34559269292157252301272587
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Marcos

In San Marcos in December, humidity is 66%. With an average temperature of 25°C (78°F), this humidity feels like a warm, enveloping blanket that can make outdoor activities feel more draining, yet still enjoyable for short adventures.

December Average Humidity in San Marcos

This chart illustrates the average monthly humidity levels in San Marcos, 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 Marcos is approximately 66%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec63%62%59%59%59%68%78%79%77%77%75%67%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Marcos

In San Marcos in December, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in San Marcos.

Maximum UV Index Levels in San Marcos for December

The chart shows the monthly maximum UV Index (UVI) for San Marcos 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 Marcos typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec11121414141413131313109
Data source: San Marcos 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 Marcos Compares to Other Months

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

This table compares monthly weather conditions in San Marcos, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather25°C (78°F)3 mm (0.1 inches)63%extreme
February Weather26°C (79°F)4 mm (0.2 inches)62%extreme
March Weather27°C (81°F)5 mm (0.2 inches)59%extreme
April Weather27°C (81°F)59 mm (2.3 inches)59%extreme
May Weather27°C (80°F)269 mm (10.6 inches)59%extreme
June Weather26°C (79°F)292 mm (11.5 inches)68%extreme
July Weather27°C (80°F)157 mm (6.2 inches)77%extreme
August Weather26°C (80°F)252 mm (9.9 inches)79%extreme
September Weather26°C (79°F)301 mm (11.9 inches)77%extreme
October Weather25°C (78°F)272 mm (10.7 inches)77%extreme
November Weather25°C (78°F)58 mm (2.3 inches)75%very high
December Weather25°C (78°F)7 mm (0.3 inches)66%very high

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