These spots on some of my leaves. Any idea what this is? Wasn't there the day before.

Alan is correct.  That's just rust from morning dew.  We are starting to have cool mornings causing moisture aka dew to form more on plants and the ground.  It just means Fall is around the corner!

Rust would make sense because the humidity last night was very high, but that's not the rust I'm used to seeing. That has huge spots, and normally I've seen this during the summer:

I am extensivly experienced with rust. It cant be stopped. Every year i say i am going to get rid of it. I pull leaves on smaller plants to keep it at bay but trees it useless to try. Next year going to find the copper spray and spray it while trees are just braking dormentcy. And main tain spraying every two weeks.

I have this same thing on some of my trees also.   The rain and humidity have been brutal this year.   THat is what i am hoping it is.

Maybe it is anthracnose?

ANTHRACNOSE looks a lot more like what my leaves have in the first post, although I have no fruit to see if it'll fall off. Anyone have any more info on this?

After some research, Richie. I don't have any doubts that it's not anthracnose. I'm not sure if ficus carica can be infected like the other species of trees listed, but my theory on what happened is that a nearby tree is infected, and the wind blew some spores in the direction of some of my figs. I kid you not, you could have actually traced the path of the wind with the infected leaves. What I'm still confused about, is how bad this could potentially affect my trees if it occurs again, and how to kill it completely other than preventing anthracnose using copper sprays. If anyone has any additional information, I'd be very interested to hear it.

From: https://pubs.ext.vt.edu/450/450-604/450-604.html

It says, "the spores are blown and splashed to the buds and young leaves and, with favorable moisture conditions, penetrate and infect the swelling buds and unfolding leaves. Long rainy periods help the fungus to spread rapidly."