You've got that vicious western sun where it is near the top of the UV index all of the time, and that non-existent humidity can be hard on a paint finish. You will need extra protection even with minimal rainfall.
You should be able to use Carnaubas all year around in Vegas without any trouble like we have a few hours North of you. They are very gentle if paste waxes are used. I know. I bought an older Red Mazda MX-6 that was oxidized when I bought it. Even after the oxidation was removed, liquid waxes bleed color into the applicator. Paste waxes hardly any. The synthetics I've tried also put more color on the cloth.
Here's what I would do if I had a new car.
1. Wash with Dawn to remove any residual grease and oils.
2. Use a clay bar, folding in frequently to remove any railroad dust and iron filings from the surface. Make sure the surface is mirror smooth to the touch before you finish. Usually you can keep the clay bar for use again, but with the rail dust throw it away. Mothers, Clay Magic, Erazer and Meguiars are all good products.
3. Use Pinnacle Paint Cleansing Lotion, or for a lower price check at a motorcycle dealer and get S100 Shine Enhancing Polish. This is a gentle cleaner without physical abrasives and leaves a good finish. Standard Glazes should be used later.
4. Top off with Carnauba of choice. S100 is the same as P21S for about half the price. Incredible clarity, but recoat needed about every 6 weeks on darker cars in the summer sun. Love it on lighter colors. Pinnacle is considered one of the best Carnaubas, but costs about $50.00 for 6 ounces. Too rich for me when many on this site say P21S/S100 produces similar results. Both of these are extremely easy to apply and remove if the instrucdtions are followed correctly. P21S looks absolutely fabulous.
Meguiars #26 Hard Yellow Wax is very good and inexpensive. Lasts about as long as P21S, but is harder to apply and remove. Costs only about 25% of P21S however. Depth of shine is equal, but reflections are slightly less crisp.
3M Perfect-It Show Car Paste Wax from 3M.com, or NAPA auto is probably the best wax you can buy for $15.00. It has twice the wax, 12 ounces, and has ASE which is a flourine polymer that bonds to paint. If done on a cool surface it is easy to apply and remove. It gives a nice wet look to darker cars and has nearly the reflective clarity of P21S.
I just did some testing where I had Meguiars #26 and P21S on the roof and trunk of my Blaze Red Mazda. 3M Perfect-It Paste Wax was put on the hood a month before. When it was first done, they all looked great. My wife parks every day in a sunny parking lot. Well after 6 weeks the #26 and P21S no longer beaded when washing. The Perfect_It still looked good. I've gone up to 4 months in winter snows and rain and it still beaded. It also layers if you wait a few weeks between coats for an even deeper shine.
On a new car I would do this in cooler temperatures, in the shade, and by hand. I recommend microfiber or foam applicators.
Last year I took my 10 year old Subaru into a Toyota parking lot, and without a doubt the best looking finish was on my car. So I'm sure you can make that new car look better than new:xyxthumbs