With the sweltering heat here how can you keep your lawn looking good?  
To be honest, it's tough during this dry season with the temperatures soaring.  St Augustine, especially, needs a lot of water.  Usually, you can water a couple of times a week and supplement with rainfall.  Without rainfall, many lawns are starting to turn brown.  The only remedy is to water slightly more than you did before.  You can still keep to two days a week but maybe increase the amount of time per zone to make up for the excessive heat we are getting without any precipitation.  Once the rainy season starts or your grass recovers you can always reset the zone for less time.  You may not have to do this for all zones.  Take a look at the grass blades.  If they are thin and crunchy, they need more water.  If they are lush green and wide, they are doing just fine.  

St Augustine grass is a fast growing, widely used, warm season grass used extensively here in Florida. 
St Augustine spreads on top of the ground.  If you mow the grass too low, you can scalp the grass and discourage routing.  St Augustine grass should be mowed at a height of 2.5 to 4 inches.  You should not remove more than 1/3 of the blade of grass to avoid leaving clumps in the yard.  By mowing more often you will avoid grass clippings and enhance the beauty of the lawn. 
Watering of St Augustine should be done bi-weekly during the growing season with at least 1" - 1 1/4" of water per week.  The best time to water is in the early morning before sunrise.  Watering while the sun is out will evaporate the water too quickly and not allow it to soak into the soil.