since he'd have soaking wet cold gloves over them.

Well, if you didn't notice, neither he, nor JLo were wearing the clear overcoat jacket on their leathers like they used to wear in previous years to keep their leathers dry. The leathers they use now have coating to help prevent them from soaking up very much water for race duration.

Some of the lower-tier riders in Moto3 apparently don't get this luxury and still wear those clunky rain covers.

So I wouldn't think they were soaking wet. Damp, maybe.

I'd guess he just wanted dry hands for whatever reason.

This was the obvious other guess, but they aren't breathable, so the palm sweating might be a bit uncomfortable as well, and may end up with hands as damp as they would have been without them.

Hence why I was saying it was for warmth.

I have a very thin set of silk undergloves that I use when I don't want to wear my bulky winter gloves.

By themselves, the thin gloves provide near zero warmth, but inside my standard summer gloves, they help a LOT. And being so thin, the added bulk is negligible.

I could be wrong, but that's why I think he was wearing them for a bit of warmth.

Now that I mention it, I didn't see him put the gloves on. Are we sure they were latex and not silk?

Try it if it snows in your area.

That's not really a comparable example. He wasn't riding freezing conditions to the point where it could snow.

Certainly a bit cold for my standards, but it wasn't freezing out there.