January Weather in San Diego, Mexico

Last updated: August 27, 2025

In San Diego, Mexico, the average temperature in January hovers around 13°C (55°F), with a range that can dip to a cool 3°C (38°F) or soar to a warm 27°C (81°F). Expect 88 mm (3.5 in) of precipitation over approximately 11 days, accompanied by an average humidity level of 88%.

January Temperature in San Diego

In January in San Diego, the average temperature is 13°C (55°F). Maximum temperatures can reach 27°C (81°F), while minimum temperatures can drop to as low as 3°C (38°F). This variation makes it advisable to pack layers for your travels, ensuring you're prepared for both warm days and cooler evenings.

January Weather in San Diego: Daily Temperature Highs, Lows, and Averages

The chart illustrates January temperature patterns in San Diego, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In San Diego, January typically has an average temperature of 13°C (55°F), with highs reaching up to 27°C (81°F) and lows dropping to around 3°C (38°F).

Data source: Temperature data for San Diego generated using information from the Copernicus Climate Change Service.

January Precipitation in San Diego

In San Diego in January, the total precipitation amount is 88 mm (3.5 in) spread over 11 days.

January Precipitation Trends in San Diego

The chart displays monthly precipitation patterns in San Diego, with values for each month alongside January’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how January’s conditions compare to those of other months. In San Diego, January typically receives around 88 mm (3.5 inches) of precipitation spread over approximately 11 days.

Data source: Precipitation data for January generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

January Humidity in San Diego

In San Diego in January humidity is 88%. With an average temperature of 13°C (55°F), this humidity feels like a damp chill that clings to your skin, making it essential to dress in layers while exploring, as the moisture in the air can lead to a rather uncomfortable experience for traveling.

January Average Humidity in San Diego

This chart illustrates the average monthly humidity levels in San Diego, with January’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In January, average humidity in San Diego is approximately 88%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for January generated using information from the Copernicus Climate Change Service.

January UV Index in San Diego

In San Diego in January, 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 Diego.

Maximum UV Index Levels in San Diego for January

The chart shows the monthly maximum UV Index (UVI) for San Diego in January, 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 January, the maximum UV index in San Diego typically reaches 9, which falls under the very high exposure category.

Data source: San Diego January 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 January Weather in San Diego Compares to Other Months

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

This table compares monthly weather conditions in San Diego, showing how January’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	13°C (55°F)	88 mm (3.5 inches)	88%	very high
February Weather	15°C (58°F)	64 mm (2.5 inches)	86%	extreme
March Weather	16°C (61°F)	93 mm (3.7 inches)	84%	extreme
April Weather	18°C (65°F)	133 mm (5.2 inches)	81%	extreme
May Weather	19°C (67°F)	190 mm (7.5 inches)	82%	extreme
June Weather	19°C (66°F)	262 mm (10.3 inches)	81%	extreme
July Weather	18°C (65°F)	210 mm (8.3 inches)	81%	extreme
August Weather	18°C (65°F)	291 mm (11.4 inches)	82%	extreme
September Weather	18°C (65°F)	339 mm (13.3 inches)	86%	extreme
October Weather	17°C (63°F)	217 mm (8.5 inches)	90%	extreme
November Weather	15°C (59°F)	111 mm (4.4 inches)	91%	very high
December Weather	13°C (57°F)	51 mm (2.0 inches)	91%	very high