Summer Temperatures in the High 80's to mid-90's

My plants are wilting!  Watering twice a day now.  Getting sunburnt in the process.  I water early mornings and about 6-7PM so the plants have a chance to "dry out" a little from the watering.  I know that plants hate to be drippy wet during the night unless it is rain type watering.  Wonder what the difference is.