When to make trip to desert southwest?

I've camped in the southwestern deserts for decades, and if i had to pick one month to go (between 2000 and 5000 ft.) it would be November. Usually dry. Cool but not frigid. For low altitudes, like Death Valley, it would be January. But you never know. You are just working with weather service averages. Once we did Death Valley in January in an El Nino year. It rained most of the 5 days we were there. Luckily, the jeep trails were sand and rock, not mud, so the rain soaked in quickly. On this last day of June that sound pretty good. If seeing wildflowers (and that's a crop shoot too) is your thing, the Desert USA website is a bible with up to date info just days old with lots of fine pics. The time frame would be between the 3rd week of Feb. to about last week of March, depending. And that's a big depending: if and how much precip. We only go during floral season if the outlook is good for flora.
jefe