Last updated: August 26, 2025
In December, the average temperature in San Bruno, Mexico is a comfortable 17°C (63°F). You can expect the temperature to range from a cool 9°C (48°F) at its lowest to a pleasant 27°C (81°F) at its peak. During this month, precipitation is minimal, with an average of just 9 mm (0.4 in) of rain falling over 1 day. Additionally, the average humidity hovers around 72%, contributing to a refreshing atmosphere.
In December in San Bruno, the average temperature is 17°C (63°F). Maximum can reach 27°C (81°F), and the minimum can be as low as 9°C (48°F). This pleasant climate makes San Bruno an ideal destination for travelers seeking mild and comfortable weather.
In San Bruno in December, the precipitation amount is 9 mm (0.4 in) over the course of 1 day.
In San Bruno in December, humidity is 72%. With an average temperature of 17°C (63°F), this humidity feels like a muggy embrace, making outdoor activities a bit sticky and requiring plenty of hydration for a comfortable travel experience.
In San Bruno in December, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in San Bruno.
UV Risk Categories
Weather in San Bruno varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in San Bruno, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 16°C (62°F) | 10 mm (0.4 inches) | 71% | high |
| February Weather | 17°C (63°F) | 5 mm (0.2 inches) | 66% | very high |
| March Weather | 19°C (66°F) | 8 mm (0.3 inches) | 58% | very high |
| April Weather | 22°C (72°F) | 0 mm (0.0 inches) | 52% | extreme |
| May Weather | 24°C (76°F) | 0 mm (0.0 inches) | 51% | extreme |
| June Weather | 29°C (84°F) | 1 mm (0.0 inches) | 51% | extreme |
| July Weather | 31°C (88°F) | 8 mm (0.3 inches) | 60% | extreme |
| August Weather | 31°C (88°F) | 14 mm (0.5 inches) | 73% | extreme |
| September Weather | 29°C (85°F) | 39 mm (1.6 inches) | 76% | extreme |
| October Weather | 26°C (79°F) | 6 mm (0.2 inches) | 72% | very high |
| November Weather | 22°C (71°F) | 10 mm (0.4 inches) | 72% | high |
| December Weather | 17°C (63°F) | 9 mm (0.4 inches) | 72% | moderate |