Quick break from Phoenix....plenty of time to leave at noon, get to Joshua Tree Park in time to do the Geology Tour Trail drive (no you don't need 4x4) and take a nice walk up Ryan Mountain. Very scenic and I think we picked the perfect time: mid-March, a little before sunset, with about 70deg temperatures.
A campfire must be extinguished by drowning it with water, stirring with a shovel, and repeating that process until the campfire is cold to the touch. A campfire is still a danger if it has any trace of heat, and must not be left or abandoned. Wildfires can begin by abandoned campfires that rebuild heat on windy days and then blowing embers ignite surrounding grasses and brush.