One true test is to smoke a cigar that's been resting in your humidor for a week or two. If it smokes bad (burning hot, harsh, really black/dark ash) then it is too dry. If it is squishy and you always have to re-light, then it is too moist.

If it's the first scenario, then your Hygrometer is reading correctly and you just have to leave a shot glass full of water in your humidor during the winter months. If it's the later, your Hygrometer is reading wrong and you have too much moisture.

If it smokes just fine, you don't have to worry. Humidity fluctuates and it's not exact science when you keep cigars. If it smokes fine, leave it be and hopefully in the summer it'll correct itself. If you have issues like ripped wrappers and so forth, then definitely worry.

You are just starting out. I freaked out when my humidity was 1% off. Now, I don't even bother checking (I use Beads), unless I experience consecutive bad smokes.

Andrew