The summers can tend to be hot and muggy; the winters are short, cold, and windy; and it is partly cloudy year-round. Over the course of the year, the temperature typically varies from 41°F to 96°F and is rarely below 28°F or above 100°F.
Based on the beach/pool score, the best time of year to visit San Marcos for hot-weather activities is from late May to mid-September.
The length of the day in San Marcos varies significantly over the course of the year. In 2020, the shortest day is December 21, with 10 hours, 13 minutes of daylight; the longest day is June 20, with 14 hours, 4 minutes of daylight.
Rain falls throughout the year in San Marcos. The most rain falls during the 31 days centered around May 24, with an average total accumulation of 3.9 inches.
The least rain falls around August 1, with an average total accumulation of 1.3 inches.
The windier part of the year lasts for 7.8 months, from October 29 to June 23, with average wind speeds of more than 9.3 miles per hour. The windiest day of the year is April 1, with an average hourly wind speed of 10.8 miles per hour.
The calmer time of year lasts for 4.2 months, from June 23 to October 29. The calmest day of the year is September 4, with an average hourly wind speed of 7.9 miles per hour.
The risk of tornado damage in San Marcos is lower than Texas average and is higher than the national average. The tornado index value is calculated based on historical tornado events data using USA.com algorithms. It is an indicator of the tornado level in a region. A higher tornado index value means a higher chance of tornado events. The tornado index for San Marcos ids 170.75, as compared to Texas which is 208.58, and the U.S. which is 136.45.
The chance of earthquake damage in San Marcos is about the same as Texas average and is much lower than the national average. The earthquake index value is calculated based on historical earthquake events data using USA.com algorithms. It is an indicator of the earthquake level in a region. A higher earthquake index value means a higher chance of an earthquake. The earthquake index for San Marcos is 0.01, as compared to Texas which is 0.04, and the U.S. which is 1.81.