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.
The coast's nighttime average low temperatures for the year range from as warm as 58 degrees F (14 Â°C) at San Diego to as cool as 42 degrees F (6 Â°C) at Klamath. In the north, the year's ocean temperatures average 52 degrees F (11 Â°C), while in southern California the water is at least 10 degrees F (5 Â°C) warmer. The high and low air temperatures are normals for the years 1981 to 2010.