Humidity in boa's tank

[Craiga 01453]

Thanks I will give it a try tonight and see if it is more accurate. It is a glass enclosure. I try and cover some of the top screen as well to keep humidity in. Maybe it's just the meters wrong. IDK why it's so moist in there but the humidity reads always around 40% I will also switch her substrate to more fresh and dry and will avoid getting the substrate itself wet.

It sounds like you're on the right track. Glass can be tough to get temps and humidity dialed in, especially during winter months. But it can be done with a few tweaks.

I wrap my glass enclosures in 1/2" foam board insulation. I cover the back, sides and top (leaving room for a heat lamp and a little air flow.
The insulation locks heat in, which allows the heat sources to run less. Less artificial heat = less evaporation so less humidity loss. It also saves on the electric bill.

Covering the screen top as much as possible will go a long way too. And if you've got room to add a second water bowl that will help as well.

...and like you said, due to the hygrometer being inaccurate your humidity may already be perfect??