In January, San Marcos typically sees daytime highs of 30.4°C and overnight lows around 17.6°C. Compared to the annual average high of 30.2°C, January runs +0.2°C.
January in San Marcos averages a daytime high of 30.4°C and an overnight low of 17.6°C.
January runs +0.2°C compared to San Marcos's annual average high of 30.2°C, ranking #5 of 12 months by warmth.
Plan for daytime highs near 30.4°C and cooler evenings around 17.6°C.