From my understanding Tesla roofs block 98-99% UV Rays. I also didn't know they can turn orange in heat.I have Tesla Model 3 with all glass roof. We've been in over 100 degree weather and direct sunlight for long period of time while driving without any issue. I was planning to get the roof shade insert initially but really have no need.
As for the snow, I don't know. I'm in SoCal so unless I go to the mountains it doesn't happen. But as JulianD mentioned above, I would imagine (since Tesla has it) that you can turn on the interior temperature setting prior to getting into the car. Once the temperature is reached, then maintaining it shouldn't be a big deal - in either direction.
When I ordered the R1S, it didn't bother me at all that it has a glass roof.
People in temperate climates all over the world have begun noticing that Tesla’s glass roofs sometimes look a rusty orange colour. Here’s what’s behind it