December Weather in San Marcos

Last updated: March 2, 2024

The weather in San Marcos, United States, during December is characterized by an average temperature of 14°C (57°F). Highs can soar to 25°C (77°F), while lows may dip to 4°C (40°F). Typically, the humidity level in San Marcos throughout December hovers around 74%.

4°C (40°F)

Minimum temperature

14°C (57°F)

Average temperature

25°C (77°F)

Maximum temperature

74%

Humidity

Precipitation and Sunshine hours

In December, San Marcos averages 70 mm (2.7 inches) of rainfall, typically over the course of 6 rainy days. The month enjoys an average of 9 hours 59 minutes of daylight, with the sun shining for approximately 7 hours 20 minutes each day. Additionally, there is a 48% probability of sunny days during this period.

70 mm (2.7 inches)

Precipitation

6 rainy days

Rainy days

7 hours 20 minutes

Sunshine hours

48%

Chance of sun

UV Index

In December, the UV Index in San Marcos reaches a maximum of 4, indicating a level of Moderate exposure. The most intense UV radiation typically occurs between 11:00 and 13:00, during which unprotected skin may burn in as little as 30 minutes.

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
  07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00
UVI 1 1 2 3 4 4 3 2 1 1 0 0 0
Exposure Low Moderate Low
Time to burn 45 min 30 min 45 min

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