How to tell if baby is cold?

We live in Georgia (US) and temperatures are starting to drop. But I’m used to the heat, and before baby we kept it at 77 inside.

We lowered it to 73 to keep baby cool enough because she would get flushed or sweaty, but now temperatures are dropping on their own.

How can I tell if she's getting too cold at night? We stopped swaddling at 4 weeks because she was rolling, so no swaddles. Just footie pajamas was fine when it was 73– her fingers would be cool but not cold during nightly diaper changes, which seemed about right.

But what do y’all think? I don’t want to be relying on touching her hands to figure out if she’s warm enough.