Royals are far more frost tolerant than Wodyetias, but still may not look all that great in marginal climates, particularly if they are windy ones. I great a royal in the San Fernando Valley from a 1 gal... did great until it popped its crown above a wall... then it looked pretty sad as the winter winds whipped its leaves to shreds... still, it is not dying and still growing quite fast. I also have a Wodyetia but it is firmlly planted against a house facing south.. if it grows above the top of the house, my guess it's gonna croak.

Its not so much windy as breezy here by the bay a few miles inland. I can drive over the hills across the street up 250' elevation and down into a valley(a greenbelt park) in early spring...and ahhh,no wind,warm. But,that breeze is what keeps frost off in winter.
Also Dr, My summer ave from June to now is about 75f. lows are in the 55-60f range with the 60's in mid June starting. Winter days mostly high 50's low 60's. But loads of sun.
Worth a Royal try?

There are different types of "Royal" palms. Roystonea regia is the most cold tolerant. They can take high 20's. Just make sure you get a palm that was grown in CA and not FL or HI. They will already be hardened.

I agree, royal palms are a lot more cold tolerant and they are also more tolerant of dry and cooler temperatures than foxtail palms. I think you might be able to manage both in Cali, but I've seen more royals and some of them look really nice!
-Alex