Yes, I know you have it dry. So do I. I think the roses are handling the triple digit temps better than I am
Managing spider mites with just water is soooo much easier with just washing down the roses using the hose and not bothering with mixing any solutions and using a sprayer and gets the job done in less time. If you are using a drip system, it is even more important to wash the plants down.
Once in a while, I'll find where I may have missed a spot and the mites have gotten started, but I just am more careful with that rose and the infestation is totally gone within a couple of days and has not spread to the whole plant.
Good luck with your roses.