I have four of these scattered around the house.
https://www.amazon.com/gp/product/B08LKC4K15/
They're pretty accurate and consistent. Wifey has a huuuuge book collection and recently we found some light mold on some books, so now she's like a hawk looking for humidity. We have these on bookshelves and if we see one go above 50%, we roll in the dehumidifier and fire it up for a while. You might try one of these near your windows to see what the humidity level is right there.
Our bedroom has heavy blackout drapes, so we have to keep them open during the day to keep condensation from building up on the windows. We also have a whole house humidifier built into the furnace, but it's off now due to the aforementioned mold issue. Hasn't been uncomfortably dry this year anyway, so we don't really need it.