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December Weather in San Guillermo, Mexico

Last updated: August 27, 2025

In San Guillermo, Mexico, the average temperature in December hovers around 11°C (51°F). Expect a chilly minimum of -9°C (16°F), while highs can reach up to 27°C (81°F). With 18 mm (0.7 in) of precipitation over the course of 2 days and an average humidity level of 84%, this month promises a mix of cool and damp conditions.

December Temperature in San Guillermo

In December in San Guillermo, the average temperature is 11°C (51°F). Maximum temperatures can reach 27°C (81°F), while minimums can drop as low as -9°C (16°F). Travelers should be prepared for a wide range of temperatures during their visit.

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

The chart illustrates December temperature patterns in San Guillermo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Guillermo, December typically has an average temperature of 11°C (51°F), with highs reaching up to 27°C (81°F) and lows dropping to around -9°C (16°F).
JanFebMarAprMayJunJulAugSepOctNovDec515663707782797872675951
Data source: Temperature data for San Guillermo 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 Guillermo

In San Guillermo in December, the precipitation amount is 18 mm (0.7 in) over the course of 2 days.

December Precipitation Trends in San Guillermo

The chart displays monthly precipitation patterns in San Guillermo, 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 Guillermo, December typically receives around 18 mm (0.7 inches) of precipitation spread over approximately 2 days.
JanFebMarAprMayJunJulAugSepOctNovDec6545630796687341418
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in San Guillermo

In San Guillermo in December humidity is 84%. With an average temperature of 11°C (51°F), this humidity feels like a damp chill enveloping you, making it seem much colder than it actually is, and can dampen your spirits while traveling.

December Average Humidity in San Guillermo

This chart illustrates the average monthly humidity levels in San Guillermo, 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 Guillermo is approximately 84%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec78%71%60%52%49%50%65%70%79%77%83%85%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in San Guillermo

In San Guillermo 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 Guillermo, you can refer to this Hourly UV Index in San Guillermo.

Maximum UV Index Levels in San Guillermo for December

The chart shows the monthly maximum UV Index (UVI) for San Guillermo 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 Guillermo typically reaches 6, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec69111313131313121086
Data source: San Guillermo 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 Guillermo Compares to Other Months

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

This table compares monthly weather conditions in San Guillermo, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather10°C (51°F)6 mm (0.2 inches)78%high
February Weather13°C (56°F)5 mm (0.2 inches)71%very high
March Weather17°C (63°F)4 mm (0.2 inches)60%extreme
April Weather21°C (70°F)5 mm (0.2 inches)52%extreme
May Weather25°C (77°F)6 mm (0.2 inches)49%extreme
June Weather28°C (83°F)30 mm (1.2 inches)50%extreme
July Weather26°C (79°F)79 mm (3.1 inches)65%extreme
August Weather25°C (78°F)66 mm (2.6 inches)70%extreme
September Weather22°C (73°F)87 mm (3.4 inches)79%extreme
October Weather19°C (67°F)34 mm (1.3 inches)77%very high
November Weather15°C (60°F)14 mm (0.6 inches)83%very high
December Weather11°C (51°F)18 mm (0.7 inches)84%high

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