Located in the Mojave Desert between Los Angeles and Las Vegas, the Mojave National Preserve covers 1.6 million acres of diverse desert habitat. I have visited the preserve many times and usually I go in late winter or early spring.  The weather was good with temperatures in the 50's F during the day and falling to below freezing at night, especially in the higher altitudes. I prefer to explore the less visited areas on 4WD roads and tracks.