If you have modern windows, the amount of UV transmission is very very small.

I have an outside BBQ area with 12 ft or so of granite counters. The counters face west and south. I am in southern CA so they get baked by the sun year round. No issues with the granite being in the sun.

Your new windows should have some UV protection, right? You could always use a window film for even more UV protection. I would worry less about the counters and more about cabinets or wood floors that will be exposed to direct sunlight ... those will certainly fade. The wood fading isn't obvious until you move one of the area rugs! It happens and isn't something I dwell on. Any future owners will probably refinish the wood floors before they move in, just like we did.

I wouldn't worry about quartzite, which Taj Mahal is. My quartzite was sitting out in the sun at the fabricator's for well over a year with no problems.

That you very much for the replies!! Yes, the windows will have some UV protection (they have the low-e glass). Exactly how much UV they block, I'm not sure (can't seem to find the percentage of UV blocked online).

I will definitely ask if the granite has resin on it. Is there a way I can tell by looking at it or testing it myself??

Thanks again!!

Consider that shiny counters reflect sunlight. It’s something we didnt expect when my parents switched from formica to polished granite. The glare is migraine- inducing during a certain hour of the day.

Hmmm.....Emily, that's a very good point. Never thought about the glare, but with the polished surface, it will definitely reflect!