San Marcos (CA) Weather & Climate: Best Time to Visit

In San Marcos, seasonal changes bring about a moderate variation in temperatures. Average maximum daytime temperatures range from a comfortable 30°C (86°F) in August, the warmest time of the year, to a pleasant 19°C (66°F) during cooler months like January.

At night, you can expect temperatures ranging from 17°C (63°F) in August to around 7°C (45°F) during January.

Check out our detailed temperature page for more information.

Temperature ranges by month

San Marcos typically sees modest rainfall throughout the year, with an average annual precipitation of 309 mm (12 in). Significant seasonal changes in precipitation occur throughout the year. In the wettest month, December it receives moderate rainfall, averaging 79 mm (3.1 in) of precipitation, recorded across 8 rainy days. In contrast, the driest month June brings less rainfall, with 0.6 mm (0.02 in) over a single rainy day. For more details, please visit our San Marcos Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

While the amount of sunshine in San Marcos varies throughout the year, all seasons offer their own charm. Enjoy up to 10.1 hours of daily sun in July, and experience slightly darker atmosphere in February, with about 7.7 hours of daily sunlight.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Daily percentage of sunshine

The relative humidity is high throughout the year in San Marcos.

The city experiences its highest humidity in July, reaching 75%. In January, the humidity drops to its lowest level at 64%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year