McDonald's change their sign to turquoise to better fit in with the aesthetics of the town

It may be a restriction for the shopping center that they have no choice about. I've seen it in the really wealthy area shopping centers where every business is required to have not only the same color but sometimes even the same font on their signs

This opened in the early '90's. They initially called them teal green arches, though. It's in Sedona, Arizona. The city has absurd restrictions on sign size, color, height, lighting, and building colors. The signs are so low, small, and dark, you'll end up driving by smaller shops if don't already know were they're at. Everything just blends together.

No

Is this somewhere in New Mexico?

Oro Valley Az has the same kind of rules for signs and buildings. It's like the whole city is an HOA.