Sounds like a stupidly easy question to find out with a quick internet search, but it’s not.
I don’t want to know the average surface temperature, or the average ocean surface water temperature, or read another article about climate change.
But that’s all I found in the past hour.
I’d like to know the average temperature of all molecules that comprise earth, or a best guess scientific estimate.
After cruising the comments and reading your post twice I propose the following because I’m that asshole today:
Go by layer.
Okay, so, assload insta-death ballpark Celsius in the center, okay fine. Maybe median this one. Then, consider some other identifiable layer(s) between there & surface, with some more eyeballing. THEN, for good measure, as many surface temps you can get for sea/land/air if you have chosen the range to include atmosphere.
Report back. I’m half asleep and haven’t checked my work. Also. I only ever need half a reason to suggest implementing excel to assist in your calculations 😂 I’m so sorry