My area is hot and dry too for about 7 to 8 months really no rain here, with triple digit heat in summer most of the time, so what I did was to choose an area where my orchids will get morning sun then shade/part shade in the afternoon. Most of my orchids are in containers, in mixed bark.
On days that we get a forecast of 100F ++ I make sure to give them a good shower in the morning, I do not seem to have a problem overwatering them, it just dries out very fast anyways. I sometimes have to do a 2nd shower for them, just have to, our humidity is so low sometimes in single digit. Plus I have an outdoor fountain beside them, so I think it helps when air blows through the water as it flows. I think what helps the orchids survive during these dry hot days is the air flow around them and the shade. Something that helps them cool down from getting overheated.
