You can visit the desert southwest and Las Vegas region (campervans can be rented from Campervan North America's Las Vegas location) year-round. The time of year you decide to come will determine what destinations are best suited, weather-wise, for campervaning.
If it's a winter getaway you're interested in you might find yourself in the Death Valley area. If you're on summer vacation you'll probably choose locations at higher altitude like Bryce Canyon and the North Rim of the Grand Canyon.
The climate of the desert southwest is typically dry and sunny, and generally one of the warmer places in the continental US no matter what the time of year.
The tales you may have heard about the 'dry heat' of the desert are true! Though very hot at times, the lack of humidity makes high (and low) temperatures more tolerable than you might expect.
As mentioned earlier, you can come to the desert southwest any month of the year, and within 300 miles vary the weather by elevation and latitude or proximity to the ocean. As a rule, when you go up 1000 feet in elevation, you lose 7 degrees Fahrenheit in temperature.
Las Vegas is located appproximately 2100' above sea level while not that far away at the North Rim of the Grand Canyon you are at 8000'. So, in the winter, the roads to the North Rim can be closed because of snow whereas in August in Las Vegas it might be 110°F but only in the 80’s at the North Rim.
So what does this all mean when planning a vacation?
You need to strive to be as high as you can in the summer regardless. The North Rim of the Grand Canyon, The South Rim of the Grand Canyon, Bryce Canyon, Yosemite and Great Basin national parks are going to be cooler because of their elevation.
I have spent winters in Iowa, Idaho, Ohio, Fort Worth, TX, and Nevada in my life. Nevada, especially if you would want to camp, is BY FAR nicer than any of the other areas I have experienced. The main reason is that it is generally sunny.
Once again the key here is elevation and gauging the current weather conditions. Death Valley, Joshua Tree, Mojave Natural Preserve, Sonoran National Monument, and Organ Pipe National Monument are all perfect places to go in December or January, or while it is really nasty where you are from! You can realistically expect to see a few days each week in many of these areas hit the 70’s. This would be in Death Valley and the areas in Southern Arizona.
Nearer to Las Vegas, it depends. If a cold front comes through, it can be highs in the low 50’s and a bit chilly, but still sunny. It also can be upper 50’s and perfect. Once the end of January comes, it warms. All of a sudden in Las Vegas, it is in the low 60’s then soon it hits 70°F some days in mid-February or so. By this time of year you can start looking at going to places like Zion, and Bryce, but watching the weather is still important. Once March hits, it is another notch nicer, and allows you to venture into more mid-elevation locations.
The first day of spring finds the following average temps at these locations:
So as you can see, it is pretty nice in most places. If cactus and the warm weather places are what you desire, do them now. If you want to do more of a Utah swing, possibly waiting until April is a good call.
My last bit of advice on your vacation is to look at where you want to go, and try and start your loop in the direction of where day length can possibly affect the weather and temps where you are going. Lets say that you come in Late October, and want to go to the Grand Canyon, Zion, and Death Valley. Start your loop by going to the higher elevation places. Why? Because in the fall, each day gets shorter, thus making it cooler, so you are going where it will be cooler prior to where it should be hotter. Get it? In the spring do the exact opposite.
Owner, Campervan North America LLC