From someone who knows:
I rode in 95f 95% heat for YEARS, and wore long sleeve shirts.
1. Darker colors protect better but are slightly warmer.
2. Long sleeves protect much better than sun screen. In extreme cases (you are REALLY sensitive AND out all day at the equator) use both
2a. Sunscreens protect a lot in some spectrums and less in others but rarely in all of the harmful spectrum and never over long term. Some sun screens can have long term effects on you and the environment long after you wash it away.
3. When wearing long sleeve wicking material in 95/95 weather, the first 5-10 minutes WILL feel really hot until you sweat, even in VERY humidity climates.
4. Tighter fit helps with cooling. Looser clothing creates an air pocket that will trap heat.
5. I've noticed that wicking material works better with no hair underneath, the hair, if thick enough, causes an air gap.
6. in dry and sometimes wet conditions, and your sweat is dripping off of you: that is useless sweat. Unless it evaporates, it does nothing to cool you. The increased surface area of the material allows for more efficient evaporation.

TL;DR
You pale?
Cover up.
Sunscreen if you can't

Or pay the price down the road