Atenolol and chlorthalidone combination is used to treat high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly.
San Marcos Average Weather. 1  The highest monthly average temperature in San Marcos for August is 70 degrees. 2  The lowest monthly average temperature in San Marcos for January is 55 degrees. 3  The most monthly precipitation in San Marcos occurs in January with 2.3 inches.  The air quality index in San Marcos is 22% worse than the national average.
San Marcos is a North County city and a principal city of the San Diego metropolitan area. As of 2010, the city had a total population of 84,391. Outside the San Diego-Tijuana region, it is best known as the home of California State University, San Marcos.