Consider some sunscreen arm sleeves, I started using them about 3 yrs ago. They are comfy upto low 90s F for me
(and humidity never less than 50-60%) especially while moving and appear to have ~40-50 SPF ratings. You might
also look into some of the neck covers that attach to the helmet and depending on how much hair you have a
full coverage scalp (doo-rag) such as Halo or similar. I used to get tiger stripes on my scalp every summer before
using a full scalp cover, which also helps with the sweat and is good down to the low 30s F in winter.
https://www.amazon.com/s/ref=nb_sb_s...d=UF7DIUFMX7PA

There was a post by a dermatologist on his head cover gear which was a bit overboard but kept his entire head protected.
Don't forget sunscreen on the face.