Welcome to the board.

First off, loose the cedar insert. It is probably american cedar or red cedar if it was used in your closet. It is not the same as "spanish" cedar used in Humidors. As a side note spanish cedar is not actually cedar. There are a number of reasons not to use the red cedar, which can be found here or google. The Tube should help but your digital probably isn't 100% accurate, it is probably a few percentage points off. As for the analog, do the salt test. Again use the search feature on the board for info on procedure.

finally temperature and out side humidity effects the relative humidity also.

There have been lots of discussions back and forth on the board so if you search your questions you will probably find the answers.