On Sat, 30 Sep 2017 12:39:31 -0700 (PDT), wrote:

I imagine there is a fair difference due to the color of the shingle. I know for a fact that black roofs are appreciably hotter than white roofs, but I can't tell you the difference in actual degrees.

Here in the Mojave desert, I've seen roofs with white quartz rocks on
roofs placed on top of tar/shingle roofing. The white rocks refract
the heat back up. (old methods)

My roof is Spanish style concrete ~ 21 years old. Neighbor had leaks
because the valleys clogged to "stuff". At least he has cut the tree
back -- less "stuff" on the roof.